General Science

General Science

1) Planet nearest to the sun is Mercury & farthest to the sun is Neptune. (Note: Actually according the IAU, the Top most body in Astronomical Sciences, there are only 8 planets, hitherto farthest planet Pluto had been demoted to Dwarf planet in 2006. But school book mentions only 9 planets).
2) Gas law was given by Boyle.
3) Growth of the baby in the uterus is found using Ultra sound.
4) The forms of matter are 3 (Solids,Liquids & Gases), the fourth state of Matter is plasma.
5) The whether map telecast in T.V. is photographed by the satellite orbiting at a height of 36,000 km
6) The unit of work and energy is Joule.
7) Einstein got the Noble Prize for Photo – electric effect.
8) Asia’s biggest astronomical telescope is at Kavanur.
9) An example of semi – conductor is Germanium.
10) Unit of charge is coulomb.
11) Persistence of vision is the principle behind cinema.
12) The normal boiling point of a liquid is the temperature at which the vapour pressure of the liquid is equal to the atmospheric pressure.
13) The shining particles seen in the path of beam from a projector in cinema hall is due to scattering of light by dust particles in the path of the light.
14) “Decibel” is a unit of sound intensity.
15) The weight of a body is maximum at the poles,minimum at the equator & zero at the centre of earth.
16) Ball pen works on the principle of capillarity and surface tension.
17) A body will not radiate any heat energy at -273?C.
18) In a standing wave the distance between a node and adjacent antinode is ?/4.
19) A telescope and a microscope differ in that telescope has objective lens of large focal lengths and eyepiece of smaller focal lengths.
20) The centre of the Newton’s rings pattern is dark since the light undergoes a phase change ?.
21) Galvanometer can be converted into a voltmeter by using a high resistance in series.
22) Galvanometer can be converted into an ammeter by using a low resistance in paralell.
23) The apparatus used in submarines to give clear view of the objects on the surface of the ocean or ground is known as Periscope.
24) The metal is commonly used for making an electromagnet is Iron.
25) Kilowatt – hour is a commercial unit of power & watt is the general unit of power.
26) Choke is used to reduce the current in AC circuit.
27) The ozone layer protects us from ultra violet rays.
28) When a wave goes from one place to an other it transports energy.
29) A 100 watt bulb will consume one unit of electrical energy in 10 hours.
30) The solar system belongs to the galaxy called Milky way.
31) In an electric bulb, a little nitrogen or argon is introduced at low pressure to cool the hot filament.
32) An artificial satellite can be tracked very precisely from the earth by using Doppler effect.
33) The sudden fall of atmosphere pressure indicates storm.
34) The layer of the atmosphere which is responsible for the reflection of radio waves is Ionosphere.
35) Television was discovered by Baird J.L.
36) On adding a little antimony or phosphorous to germanium, we get n-type semiconductor.
37) The waves/rays produced by nuclear changes in the atom are X-rays.
38) Artificial satellites are used for TV transmission, Detecting minerals & for Space research.
39) Sound travels at maximum speed in steel & minimum speed at air (332 m/s).
40) The minimum lengths of a plane mirror in which a person can see himself in full length should be nearly half of his height.
41) If you walk towards a plane mirror at a speed of 10 cm/s, the speed does your image approach you is also 10 cm/s (with the same speed).
42) The normal temperature of human body on the Kelvin scale is 310 K or on the Celsius scale is 37º C or on the Fahrenheit scale is 98.6º F.
43) Electron microscopy is advantageous because much greater resolution is possible.
44) The phenomenon which cannot be explained by wave theory is photoelectric emission.
45) The size of the atom is 10-10m or 1 Å and that of atomic nucleus is 10-14 m.
46) The half life of a radioactive sample is 20 minutes. The fraction of the sample that will remain undecayed after 80 minute is 1/16.
47) Electrons can be accelerated to very high energies by means of cyclotrons.
48) Roentgen discovered x-ray.
49) Polariods are used in photo-elasticity.
50) Pure silicon is used in Electronic industry.
51) The lowest level energy band in a solid is called valence band.
52) Ice is slippery, when a man walks on it, for there is no friction.
53) When a vehicle passes, TV reception gets distorted due to spark plug creating electromagnetic disturbances.
54) The escape velocity of a projectile from the earth is approximately 11.2 km/s.
55) The rain-bearing clouds look black because the large number of water droplets in them absorb all the sunlight.
56) The sky is blue in colour because of the scattering of light by dust particles or air molecules.
57) Sound waves in air are longitudinal waves.
58) The density of pure water will be maximum at 4?C.
59) Penetrating power is greater in the case of ? – rays.
60) X – rays cannot penetrate through lead.
61) Copernicus discovered that the earth moves round the sun.
62) A raw egg and a boiled egg of the same appearance, same size and same mass can be distinguished, without breaking by using inertia of motion.
63) Nib of a pen is split keeping in view the phenomenon of capillarity.
64) Speeds of bodies exceeding the speed of sound are called ultrasonic.
65) Refractive index is highest for diamond (? = 1.65) & lowest for water (? = 1.33).
66) The splitting of a beam of white light into different colours is known as dispersion.
67) In winter, the temperature of the inside wall of a house as compared to the temperature of air in the room is lower.
68) At -40?C temperature, the readings of a centigrade and Fahrenheit thermometers are the same.
69) The relationship between Fahrenheit & Celsius temperature scales is F = 1.8 C + 32.
70) The relationship between Celsius & Fahrenheit temperature scales is C =
71) The relationship between Kelvin & Celsius scale is K = C + 273.
72) The electronic devices is used for digital displays in electronic calculators are LEDs.
73) The examples for non-magnetic substances are Glass, Wood & Silver.
74) According to Newton’s formula, the velocity of sound in a medium is V=E/D.
75) Light emerging from a Nicol prism has vibrations in only two mutually perpendicular directions ( those are the rays produced are ordinary rays & extra-ordinary rays)
76) The unit of refractive index is no unit
77) The examples for Insulators are Glass, Wood & Wool.
78) A radar which detects the presence of the enemy aircraft uses radio waves
79) The most basic of all test instruments is the Galvanometer.
80) The energy gap of diamond is 7 eV.
81) The positron is called the antiparticle of the electron, because it has opposite charge.
82) The radioactive decay follows N=Noe-?t.
83) ? – rays can be detected by passing them through scintillation counter.
84) Magnetron is used for the production of Microwaves.
85) The intensity of an earthquake is measured with a Seismograph.
86) Photo-cell converts light energy into electrical energy.
87) Alternating current is converted into direct current by rectifier.
88) The fuse wire is made of lead-tin alloy.
89) Sun spots are the magnetic storms on the surface of the sun.
90) The radiation with highest energy is X-ray.
91) A lift is falling freely after the suspension wire breaks. The weight of a person inside the lift would becomes zero.
92) The period of a simple pendulum will be doubled by making the pendulum length quadrupled (i.e,by making four times long).
93) The hairs of shaving brush cling together because of Surface tension.
94) Centripetal force needed to keep the moon in its orbit round the earth is provided by gravitational pull of sun.
95) Bats can fly in the dark without hitting anything because they are guided by ultrasonic waves produced by them.
96) As a person moves closer to a plane mirror the size of the image formed by the mirror remains the same.
97) Primary colours are red, blue and green.
98) A Pyrometer is used to measure high temperature.
99) Mercury thermometer is used for the measurement of very low temperature.
100) Control rods used in nuclear reactors are made of Graphite.
101) If the depth of floatation of a ship changes when it sails from the Arabian sea to the Indian ocean, it is due to change in density of sea-water.
102) A sudden decreases in the barometric pressure indicates a stormy weather.
103) The lens used to rectify long sight is convex lens.
104) The lens used to rectify short sight is concave lens.
105) A solar eclipse occurs when the moon comes between the sun and the earth.
106) A lunar eclipse occurs when the earth comes between the sun and the moon.
107) The process in which heat is transmitted without the aid of the intervening medium is radiation.
108) When the pressure increase, the boiling point rises is the principle of pressure cooker.
109) Nodes are positions of no displacement.
110) Antinodes are positions of maximum displacement.
111) Transformers are used to step up or step down AC voltage.
112) The instrument used to measure the radioactivity is Geiger counter.
113) The instrument used to test the purify of milk is Lactometer.
114) The velocity of a freely falling body Increases.
115) Momentum of a moving body depends upon both its mass & velocity.
116) The electromagnetic waves are of transverse in nature.
117) Land and sea breezes are due to convection of heat.
118) If sound persists even after its source has stopped producing sound is called reverberation.
119) Reed instrument without pipe is Harmonium.
120) The instrument which is used to measure the current flowing through a circuit is ammeter.
121) . The instrument which is used to measure the voltage or e.m.f. across any element of a circuit is voltmeter.
122) ?- particles are electrons.
123) X-rays exhibit the phenomenon of interference.
124) The phenomenon of radioactivity was discovered by Becquerel.
125) All things such as a feather, a wooden or a steel ball will fall down at the same speed in vacuum.
126) A micron is equivalent to 1/1000 mm or 10-6m.
127) The temperature at which centigrade and Fahrenheit scales give the same reading is -40? C.
128) Preferring white clothes in summer is because they are poor absorbers and good emitters of heat.
129) The scientist who discovered the relation between electricity and magnetic effects is Oersted.
130) For a transversely vibrating string, the frequency of vibration is directly proportional to its length.
131) The exclusion principle was proposed by Pauli.
132) The momentum of a body of mass ‘m’ moving with constant velocity ‘v’ is mv.
133) The period of oscillation of a simple pendulum decreases with length.
134) By the use of cold water, we can’t able to separate two tumblers stuck together into each other.
135) Water drops are spherical because of its surface tension.
136) Loudness of sound produced by a vibrating string is directly proportional to the amplitude.
137) The co -efficient of reflectivity of a perfect black body is zero.
138) Joule is the unit of energy
139) The colour of light is determined by its wave length
140) The wave theory of light was proposed by Huygen.
141) The corpuscular theory of light was proposed by Huygen.
142) The charge of an electron is -1.6X10-19 coulomb.
143) The common emitter configuration is more preferred than the common base configuration because the common emitter configuration gives high current gain, high voltage gain & high power gain.
144) Crystals having low melting points are in Mettalic bond.
145) In an AC circuit containing resistance only, the current is in phase with the voltage (e.m.f)
146) In an AC circuit containing inductance only, the current leads the voltage (e.m.f) by
147) In an AC circuit containing capacitance only, the current lags the voltage (e.m.f.) by
148) Substances which lose their electrical resistances at very low temperature are called Super-conductors.
149) Two men talk on moon they cannot hear each other at all (because there is no atmosphere).
150) In mountains, because the atmospheric pressure is low, the boiling point of water decreases.
151) By centrifugal action, we can separate particles of different densities.
152) Raman effect is due to scattering of light & total internal reflection.
153) A diamond shines brightly because it has high refractive index & low critical angle.
154) Water in a lake and nearby wells seeks the same level because of force of gravity.
155) The base of an electric iron is highly polished mainly to reduce heat loss by radiation.
156) Electronic devices that convert D.C. power in to A.C. power are called rectifiers.
157) The heating element in an electric stove is made of nichrome.
158) The least distance of distinct vision is 25 cm or 0.25 m.
159) The first satellite launched by India is Aryabhata (1975).
160) Aeroplane was invented by Orvile & Wilbur Wright (Wright Brothers).
161) The principle of a thermopile is Seebeck effect.
162) The wave theory of light was proposed by Huygens.
163) According to Kepler’s first law of planetary motion, planets move in elliptical orbits.
164) The value of gravitational constant G is 6.673×10 – 11 Nm2 Kg-2
165) The ratio of the linear stress to the linear strain of a body is called Young’s modulus.
166) For the same total weight and the same fuel supply, a multistage rocket is preferred to a single stage rocket because multi stage rocket is safer to launch.
167) 27? C can be expressed as 300 K.
168) When two resistors, each of value 10 ohms, are connected in parallel, the effective value of the combination is 5 ohms.
169) In optics, the relation between u,v and f is 1/f = 1/u + 1/v.
170) The half-life period of C14 is 5600 years. then the time required for C14 to become 1/4th of its initial size is 11,200 years.
171) Light year is the distance travelled by the light in one year
172) If an object weights 60 kg weight on earth, its weight on the surface of the moon will be 10 kg in weight.
173) A small drop of mercury is spherical due to Surface tension.
174) The unit of power of a lens is dioptre.
175) The smallest planet in the solar system is Pluto.
176) The time taken by light to travel from the sun to the earth is 8.33 sec.
177) A convex lens forms an image of a distant object on a screen. If the upper half of the lens is blocked by a piece of paper the lower half of the image will be cut off.
178) A transformer generates e.m.f.or Voltage.
179) In general, when the temperature of a metal is raised, its conductance remains the same.
180) Micro waves is used for satellite communication.
181) The colour of outer edge of rainbow will be violet.
182) The colour of inner edge of rainbow will be red.
183) When seen through a piece of red glass, the green leaves will appear black.
184) A substance is coloured due to the absorption of U.V. light.
185) Anemometer is used to measure the velocity of wind.
186) Tiruchirappalli station of All India Radio broadcasts at a frequency 1 mega hertz. This is equivalent to 10- 9 hertz
187) Waves produced on the surface of water is transverse waves.
188) Radioactivity may be natural and artificial.
189) Bending of light around an obstacle is due to diffraction.
190) A Speaker converts electrical energy into sound energy.
191) The spectrum of a source of light is called band spectrum.
192) X- rays carry unit negative charge
193) The waves received by our television sets are microwaves.
194) The relation amongst velocity (v), frequency (n) and wave length (?) is v=n/?.
195) The heavy water project is located at Kayaththar.
196) The heat of neutralisation is constant for strong acid-strong base.
197) The melting point of ice is 0?C.
198) Watt = Volt x Ampere.
199) The material which is used to make permanent magnets is steel.
200) When fast moving electrons are stopped suddenly by a metal target, X-rays are produced.
201) Liquid metal is Mercury.
202) The period of pendulum is 2.0 second.
203) The excess pressure applied at a point inside a liquid at rest is distributed equally in all directions. This principle is known as Pascal’s law.
204) Epidiascope is an instrument for projecting film on a screen.
205) The sky appears to be blue because of scattering of light.
206) The quantity of heat required to raise 2 kg. of copper from 303 K to 353 K? (Specific heat capacity of copper = 355 J/kg/K) 38500 Joules.
207) In a tape recorder, the sound is recorded on the tape by a variable magnetic field.
208) Pipe instrument without reeds is Violin.
209) Beta (?) particle is negatively charged particle called electrons.
210) Rate of change of momentum is Force.
211) Unit of Force in the M.K.S. system is Newton.
212) One unit of electrical energy consumption equal to 1000 watt per hour.
213) At sunrise and at sunset sky appears red because red light scatters less.
214) 68? Fahrenheit is equal to 20?C.
215) The force of attraction between planets is correctly given by Newton.
216) A boat moves forward when water is pushed back. The basic physical law applicable here is Newton’s third law of motion.
217) The mass of 5 litres of mercury is 5 kg.
218) Sound cannot pass through vacuum.
219) In a dynamo, mechanical energy is converted into electrical energy.
220) Induced e.m.f. is directly proportional to rate of change of flux.
221) In a step-up transformer, the number of turns in the secondary is more than in the primary.
222) In a step-down transformer, the number of turns in the secondary is less than in the primary.
223) D.C. voltage cannot be used in a transformer.
224) The condition for total internal reflection of light is a ray must pass from denser to rarer medium.
225) Sea water turns into ice at 4?C.
226) A person climbing a hill bends forward in order to increase stability.
227) Mirage observed on a road on hot days is due to total internal reflection.
228) Perspiration is maximum when temperature is high and air is dry.
229) One horse power is equal to 746 watts.
230) Mercury boils at 357?C.
231) The purity of milk is measured with lactometer.
232) Instrument used in a submarine to see over the top when it is submerged is Periscope.
233) Printing for the blind was introduced by Louis Bairille.
234) The filament of an electric bulb is made of tungsten.
235) Crystal dynamics was invented by C.V. Raman.
236) Foods stuffs remain fresh in refrigerator by preventing fermentation due to very low temperature.
237) The glass used in the preparation of lenses and prisms is Pyrex glass.
238) When the mass and velocity are doubled, kinetic energy will increase 8 times.
239) Colour formation in thin films is due to interference.
240) Photometers are instruments used to measure intensity comparison between different lights & sounds.
241) Rays from the head light of a car is rendered parallel by concave lens in front of the light.
242) The diameter of the aperture of a camera is doubled. To compensate this, the aperture time in shutter should be made ½.
243) Excited atoms gives rise to Raman Spectrum.
244) The wheel of a forward moving vehicle has 8 supporting spokes. It is photographed on a motion picture film which runs at a speed of 24 films per second. The wheel appears to be in the film, if the speed of rotation/sec. of the wheel is 3.
245) Laser is a device to produce coherent waves.
246) Transfer of heat by molecular collision is conduction.
247) The specific volume of water is minimum at 4? C
248) In an isothermal process, temperature remains constant.
249) Electron – volt is a unit to measure energy.
250) The instrument used to determine the thickness of a piece of paper is Screw gauge.
251) The condition favourable for the formation of dew is Hot day followed by a cold night.
252) Doppler effect in sound produces apparent change in frequency.
253) Boyle’s law states the relationship between pressure and volume.
254) Crystallisation is the process used to purify a soluble solid.
255) The properities of a liquid does not affect its rate of evaporation is Volume.
256) The process involves two changes of state is Distillation.
257) The function of the thermostat in a refrigerator is to regulate the temperature.
258) Small bodies from interplanetary space when enter into our atmosphere become luminous. These are called meteors.
259) The newly discovered high temperature super conductors are inorganic polymers.
260) The sound of a guitar and a violin can be differentiated because of the difference in the frequency of pitch.
261) There is a spluttering sound when water is sprinkled on hot oil because Oil and water do not mix.
262) The phenomenon of mirage is due to change in the refractive index of air with change in temperature.
263) In India, Apsara is connected with nuclear reactor.
264) The instrument used for measuring the force and velocity of wind is anemometer.
265) Tungsten is used in the manufacture of electric bulbs because it has high melting point.
266) Evaporation does not take place at all temperature.
267) Silicon is a semiconductor.
268) Electric current is the flow of free electrons.
269) The mass of an electron is 9.11×10 -31 kg or 9.11 x 10-28 g.
270) Food is cooked quickly in a pressure cooker because boiling point of water increases.
271) The unit of Surface tension is N/m.
272) Dry ice is water.
273) Solids can be identified by using line spectrum.
274) Banking of curves on roads is done to provide centripetal force.
275) A force acting on a body of 12 kg mass produces an acceleration of 1m/s2 is 12 Newton.
276) A medium can carry longitudinal wave because of elasticity.
277) When a wave goes from one place to another, it transports energy.
278) A hot body will radiate heat most rapidly if its surface is black and rough.
279) The base of the electric iron is brightly polished mainly to reduce heat lost by radiation.
280) X-rays cannot pass through bone.
281) The scientist who discovered that current can be produced in a closed conductor is Michael Faraday.
282) The densities of three liquids are D, 2D and 3D, then the density of the resulting mixture if equal volume of the three liquids are mixed is 2D.
283) When a ship floats on water, the weight of water displaced is more than that of the ship.
284) GLSV project of India is connected to missile engines for space programmes.
285) A decibel is the relative intensity of sound.
286) An antenna converts radio waves into electrical signals and vice versa.
287) The ozone layer protects us from UV radiations.
288) Through a soap film, different colours are seen by white light because of the phenomenon of interference.
289) Sound energy is converted into an electrical energy by a microphone.
290) Light from the Laser is monochromatic.
291) The unit of impedance is Ohm.
292) In an electronic watch, the component corresponding to pendulum of a pendulum clock is crystal oscillator.
293) Density of mercury is 13.6 times the density of water.
294) If the power of a lens is 5 dioptre, then the focal length of the lens is 20 cm.
295) Hershal invented ultra violet rays.
296) The surface water in a lake is just going to freeze, then the temperature at the bottom is 4? C.
297) Velocity of sound in air at a given temperature is independent of pressure.
298) Decibel is the unit of sound intensity.
299) The heater element in an electric iron box is made of Nichrome.
300) The device employed to convert electrical energy into mechanical energy is motor.
301) When a ship enters a sea from a river, it rises a little because of change in densities of water.
302) The unit of moment of force is Newton-metre(Nm).
303) The single force which effectively replaces two or more forces acting on a body is known as Resultant Force.
304) By Radiation process, the heat is transmitted from the filament of an evacuated electric bulb to the glass.
305) Specific heat capacity of water at 293 K is 4190 JKg -1 K-1.
306) The velocity of light in water is ¾ to that in air, then.the refractive index of water is 4/3 or 1.33.
307) A compound microscope is constructed using an objective of magnification Mo and an eyepiece of magnification Me. The magnification of the microscope is Mo Me.
308) Sonometer can be used to determine the frequency of a tuning fork.
309) In a tape recorder, during the reproduction of sound at the playback head varying magnetic field produces a varying electric current.
310) The direction of motion of a current carrying conductor in a magnetic field is given by Fleming’s right – hand rule.
311) Alpha rays are positively charged particles.
312) Electron was discovered by J.J. Thomson.
313) Atom bomb is based on the principle of nuclear fission.
314) Hydrogen bomb is based on the principle of nuclear fusion.
315) Proton carries a positive charge.
316) The name of the nuclear reactor at Trombay is Apsara.
317) Boyle’s law states that “Volume of a gas is inversely proportional to pressure”.
318) A spring balance is pulled by 2 persons equally with 20 newton force on its two ends. Thus it will show a reading of 20 newtons.
319) Day and night are the results of earth’s rotation around itself.
320) A body executes simple harmonic motion. Its velocity at the mid-point is zero.
321) Boiling point is an extensive property.
322) A small quantity of water placed in an open pan is allowed to evaporate. The temperature of the pan will decrease.
323) Lunar eclipse occurs on a full-moon day.
324) When a rubber ball is dropped in a hard surface, it rebounds because of elastic forces & it cannot penetrate.
325) The reason for the appearance of different colours on a soap bubble is Interference due to multiple reflection.
326) Polarization is the phenomenon which differentiates light and sound waves.
327) Polarization is the phenomenon which differentiates transverse and longitudinal waves.
328) The device used to measure voltage, current and resistance is called a multimeter.
329) The radio isotope used for locating brain tumour is Iodine.
330) Electric bulbs are filled with the gas argon.
331) X – rays travel with the velocity of light.
332) A loudspeaker converts electrical energy into sound energy
333) The transverse wave nature of light was proved by polarization.
334) Electric iron takes a long time to cool because of lesser emissivity.
335) Density of the matter is defined as mass/volume.
336) The resultant upthrust on a body partly immersed in liquid acts through the centre of gravity.
337) A transverse wave travel along z- axis. The particles of the medium must move along in x- y plane.
338) The principle of action of points is used in lighting arresters.
339) A jet engine works under the principle of linear momentum.
340) The Stefan’s fourth power law of radiation is used to find the temperature of the sun.
341) The blood circulation in muscles is due to capillary action.
342) Radio carbon dating is used to find the age of old specimen.
343) Frequency modulation is more advantageous than amplitude modulation because there will be no distortion
344) Sound is not audible in moon because it does not have atmosphere.
345) Transmission of heat from the sun to the earth is by radiation.
346) The reactor in Kalpakkam is Breeder reactor.
347) An electric fan working at constant speed consumes electric energy because of induction.
348) A person can jump higher at the moon’s surface than on the earth’s surface, since the moon has no atmosphere.
349) Rising or setting sun appears red due to the fact that scattering of light rays takes place at sunrise and sunset
350) The nature of fuse wire is high resistance and low melting point.
351) Heat waves are otherwise known as solar radiation.
352) The time taken by the light from the nearest star – centauri to reach the earth is 4.3 years.
353) When an object is transferred from the moon to the earth, Its weight increases and its mass remains constant on the earth.
354) On adding salt to water, the boiling point and freezing point of water will decrease and increase respectively
355) Vehicle tyres are inflated properly to go fast and save fuel.
356) When a body is negatively charged by friction, it gains electrons.
357) The unit of electrical conductivity is mho.
358) If the diameter of a blood vessel is halved, then the speed of blood flow will increase by 2.
359) The value of 0? absolute in Fahrenheit scale -40?.
360) Force=mass?acceleration is got from Newton’s second law.
361) A sensitive balance has an object on left pan and equal weights on its right pan. Now air is blown fast below the left pan. Then the left pan will oscillate at first.
362) Neighbouring two planets to our earth are Venus and Mars.
363) Our earth while it revolves round the sun, moves in one hour, a distance of 1 lakh km.
364) The full shape of a rainbow is Parabola.
365) The oil in the wick of an oil lamp rises up due to capillary action.
366) The lightest particle is Electron.
367) The substance has the highest specific heat is Water.
368) The surface tension of a liquid with increase of temperature decreases.
369) When a common salt is mixed with ice, the freezing point is lowered.
370) Current always flows from high potential to low potential.
371) The surface temperature of sun is 6,000 K.
372) The unit of moment of force is Newton-metre
373) Orbital velocity of a satellite close to the earth is 8km/sec.
374) The period of revolution of a satellite close to the earth is 5000 sec.
375) The unit of co-efficient of viscosity is Nsm-2.
376) Osmotic pressure of dilute solutions can be compared to laws of diffusion.
377) Radiometer is used to detect infra-red radiations.
378) TV-waves are otherwise known as Micro waves.
379) Voltmeter is voltage measuring instrument.
380) In nuclear reactors, graphite rods are used to reduce the speed of neutrons.
381) The engine power of the glide plane is 0 H.P.
382) Laws of planetary motion was given by Kepler.
383) 27?C can be expressed as 300 K.
384) Graphite is used as the moderator in Nuclear reactor.
385) Ultrasonic waves have frequency above audible range (i.e,> 20,000 Hz)
386) A simple microscope has convex lens.
387) Tesla is the unit of Magnetic induction.
388) The electro magnetic radiation travel with a velocity of 3×108 m.
389) Absolute zero, if the temperature of -273?C.
390) The discovery of electricity is attributed to Michael Faraday.
391) The flying of birds is a consequence of Newton’s Third law.
392) The value of gravitational constant is 6.673?10-11Nm2kg-2.
393) The element that has same atomic number and atomic weight is Hydrogen.
394) The Photon is non-divisible..
395) A radar which detects the presence of enemy aircraft uses radio waves.
396) The spectrum of Black body radiation is continuous.
397) When the two balls collide elastically, then both kinetic energy and momentum are conserved.
398) The planet between Earth and Mercury is Venus.
399) Noise pollution results when the sound increases beyond 120 decibels.
400) The velocity of sound in a gas is independent of humidity.
401) An astronaut in an earth satellite will observe the sky is black.
402) The colour of star is an indication of it’s temperature.
403) A rocket can go vertically upwards in the earth’s atmosphere because of the forces exerted on the rocket by gases ejected by it.
404) Raman Effect deals with quantum theory
405) In the motion of simple pendulum, the tension in the string is the greatest when the bob is at the centre.
406) Gas thermometers are those which work on thermal expansion of glass.
407) The property of the ideal gas is “There is no force of attraction, between any two molecules”
408) Microwaves are used in radar because of reflection and high frequency.
409) To an astronaut in a spaceship, the sky appears pitch dark due to the absence of atmosphere in his neighbourhood.
410) Light appears to travel in straight line. This is due to its short wavelength.
411) Madam curie became famous for her discovery of Radium.
412) Two tuning forks have same natural frequency. One of them is loaded with wax. When they are sounded together, they will produce beats.
413) Cathode ray oscilloscope is used to study wave forms.
414) The energy generation in sun and stars is mainly due to fusion of light nuclei.
415) Mercury is used in thermometer because it expands uniformly
416) Indian scientist who received the Nobel prize was Sir.C.V.Raman
417) Traffic signals are painted with paints of light reflecting.
418) According to Stefan’s law, the total energy emitted by a black body is proportional to T4.
419) All bodies large or small, fall with the same acceleration.
420) Electric charges following along a conductor are electrons.
421) In a visible spectrum, as we move from violet to red the wavelength increases.
422) Light is propagated in the form of transverse waves.
423) Water is in a beaker. Ice floats in it. If it melts, the water level will remain the same.
424) A bucket of water is suspended from a spring balance. A stone is tied to a thread and immersed into water from outside. Then the reading will increase.
425) Our atmosphere is spread up to the height of 300 km.
426) A red light is used in a traffic signal, because it has the longest wavelength.
427) Our eye is most sensitive to red colour.
428) A cloth appears green in yellow, blue in blue and dark in red light. Its true colour will be yellow.
429) A transformer transformers voltage.
430) Zener diode is used as a regulator of voltage.
431) In potentiometer experiment, when the galvanometer shows no deflection, then no current flows on potentiometer wire.
432) Isotopes of uranium are used in nuclear fission.
433) If the humidity of air increases, the velocity of sound increases.
434) The combination of properties would be most desirable for a cooking vessel are Low specific heat and high conductivity.
435) The door of an open Rating refrigerator in a room is kept open, the room will become warmer.
436) If the distance between two charges placed in air is increased two times, the force between them decreases by four times.
437) Particles which can be added to the nucleus of the atom without changing its chemical properties are Neutrons.
438) The unit of current is Ampere.
439) Light year is a unit of distance.
440) No two electrons will have all the four quantum numbers equal. This statement is known as Pauli’s exclusion principle.
441) The emission of a particle in radio activity increases the mass number by one.
442) When a metal ring is heated, its inner diameter will increase.
443) When ice melts, its volume will decrease.
444) An electric fan is switched on inside a class room. Then the air inside the room will heat up.
445) A cork floating in water in a beaker when full, comes to centre due to adhesive forces of water.
446) Rocket works on the principle of law of conservation of momentum.
447) Moment of momentum is called angular momentum.
448) Light travels 1 million times faster than sound.
449) When a glass plate is introduced between the plates of a condenser, its capacity increases.
450) Electric heater works on the principle of Joule’s law.
451) Solar cells are made up of Both Si and Ge
452) Substitute of U-235 as nuclear fuel is Plutonium-239.
453) The velocity of light in vacuum is 3?108 ms-1.
454) When milk is churned, cream gets separated due to centrifugal force.
455) Two glass plates having a little water in between cannot be easily separated because of surface tension.
456) Sound waves having which frequency are audible to human beings is between 20 Hz to 20,000 Hz.
457) We cannot see during a fog because of internal reflection.
458) Steam at 100?C is causing more injury than water at 100?C the reason is that the latent heat of condensation of steam gives additional heat energy.
459) Transformer is used to an electric lamp of low voltage on A.C. mains of higher voltage.
460) Photoelectric effect help us in converting electrical energy into sound energy.
461) Radioactivity is exhibited by all elements under proper conditions.
462) When a body is taken from the earth to the moon, its mass remains unchanged.
463) In 1.2 years, half of 64 mg. of radioactive isotope decays the amount present after 6 years is 2 mg.
464) The weight of an object would be zero when it is placed at the Centre of the earth.
465) The apparent change in frequency due to a relative motion between the source and the observer is known as Doppler’s principle.
466) Instrument used to see objects when they are hidden from direct view is known as periscope.
467) In traffic signals, red light is used to caution against danger ahead. This is because eye has maximum sensitivity for red.
468) The flame of a candle is always upwards irrespective of its position. This is because of the reaction of gravitational force.
469) A transformer works on A.C only.
470) A remote control gadget (for T.V. etc) has in it a small transmitter that emits infrared signals.
471) In a nuclear reactor, the function of an arrestor is to absorb the neutrons.
472) An electron microscope is superior to an optical microscope because it has better resolving power.
473) A particular star has mass twice that of sun. This star will end up eventually as a black hole.
474) Planets do not twinkle because they are nearer to us and so their light does not pass through the atmoshohere
475) The ozone layer in atmosphere helps in the acceleration of photo synthesis.
476) If a body is to escape from the earth’s gravitational force, it must be given a minimum velocity of 11.2 kilometre/sec
477) An aneroid barometer used no liquid at all.
478) The colour has the longest wavelength is Red.
479) Sound does not travel in vacuum.
480) A 100 watt, 220 volt lamp takes a current of 5/11 amps.
481) The material used for magnetic shielding is Soft iron.
482) The Unit of force is Newton.
483) A car is moving on a road when rain is falling vertically downwards, Rain will strike the front screen only.
484) Archimedes principle states that “A body when immersed in a liquid, experiences an upward thrust equal to the weight of the liquid displayed by it”.
485) Hydraulic brakes in automobiles work on Pascal’s principle.
486) A lens with power +1 dioptre must have its focal length equal to100 cm.
487) The velocity of light in air is 3?1010 cm/sec. Its velocity in glass whose =1.5 will be 2?1010 cm/sec.
488) During change of state, the temperature remains constant.
489) The device that is used to determine the depth of the sea is SONAR.
490) In a dry cell, the positive electrode is carbon.
491) The colour which deviates maximum during the dispersion is violet.
492) In the freezing mixture, the ratio of ice and salt to lower the temperature to -13?C is 3:1.
493) Alpha rays is not electromagnetic in nature.
494) The amount of work done in drawing a bucket of water weighing 5 kg from a well of depth of 10 metre . (g=9.8ms-2) is 490 joule.
495) Recording of sound on tapes was first invented by Poulsen.
496) The scientist who first successfully converted magnetic energy into electric energy is Faraday.
497) The rays which are not deflected by electric fields are Gamma rays.
498) Radio cobalt is used to treat the cancer.
499) J.J. Thomson discovered electrons.
500) Grass looks green because it absorbs all colours in the spectrum except green.
501) A girl is swinging on a swing in a sitting position. If she stands up and wings then the period of oscillation will increase.
502) Milk inside a thermos flask is stirred vigorously by shaking its temperature does not change.
503) A woman’s voice is shriller than a man’s voice due to higher frequency.
504) The process of nuclear fission occurs mainly in nuclear reactors.
505) The process responsible for the enormous energy in the sun is nuclear fusion.
506) Air is neither an element nor a compound.