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Current Affairs January 2024

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The best estimates of the age of the earth comes from the studies of

A. angle of inclination of the earth

B. changes in radio-active minerals in it

C. period taken by Sun's light to reach the earth

D. artificial satellites revolving round the earth

Correct Answer :

B. changes in radio-active minerals in it


Related Questions

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Like magnetic poles

A. attract each other

B. repel each other

C. neither attract nor repel

D. attract or repel depending upon the conditions

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We see the flash of lightning before hearing the thunder because

A. light travels very much faster than sound

B. sound travels faster than light

C. lightning occurs nearer than thunder

D. both travel at the same speed

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Every action has an equal and opposite reaction is Newton's law of Motion

A. first

B. second

C. third

D. fourth

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What la the minimum velocity required for a rocket to overcome earth's gravity and travel into space?

A. 18 km/sec

B. 11.2 km/ sec

C. 21 km/ sec

D. 35 km/ sec

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When ice just melts

A. there is no change in volume

B. there is no change in temperature

C. heat is given out

D. there is no change of state

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Which of the following is known as freon?

A. Liquid ammonia

B. Carbon tetrafluoride

C. Dichloro-difluoro-methane

D. Sulphur dioxide

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Changing of one element into another element is known as

A. transmutation

B. fission

C. fusion

D. radioactivity

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A nuclear reactor is said to have become 'critical' when

A. it stops due to malfunctioning

B. it starts emitting dangerous radioactive radiations

C. it is shut down to avoid explosion

D. it is ready to produce controlled energy

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The mixing up of two gases as a result of random motion of molecules is called

A. diffusion

B. effusion

C. vaporisation

D. sublimation

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For an electron orbiting in a hydrogen atom, the necessary centripetal force keeping it in orbit is provided by

A. the electrical attraction between the negatively charged electron and the positively charged porton

B. the high speed of the electron

C. the low speed of the electron

D. gravity

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Match the following:
A. Anemometer1. Measurement of power
B. Tachometer2. Wind speed
C. Dynamometer3. Revolutions per minute
D. Barometer4. Atmospheric pressure
*5. Current from a dynamo

A. A-1 B-3 C-5 D-4

B. A-2 B-1 C-3 D-4

C. A-2 B-3 C-1 D-4

D. A-1 B-3 C-5 D-2

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The tiniest of the stars belong to the group known as

A. Giant stars

B. White Dwarf stars

C. Neutron stars

D. Super-giant stars

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Which of the following revolves round the nucleus in an atom?

A. protons

B. electrons

C. neutrons

D. positrons

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Solar radiation is preferred to other sources of energy because

A. it is practically inexhaustible

B. it is the cheapest form of energy

C. it does not cause pollution

D. All of the above

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If an empty cylinder Is half ruled with a liquid, Its centre of gravity is

A. shifted upwards

B. shifted downwards

C. shifted neither upward nor downward

D. shifted upward or downward depending on the density of the liquid

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The ringing of an electric bell in an enclosed evacuated glass bell jar is not heard outside because

A. the ringing is not loud enough

B. the glass of the bell jar absorbs the sound waves

C. the bell jar is too small

D. there is no air or -any other gas in the bell jar

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When an electric apparatus is fitted with a three core flexible lead the insulation on the three wires is distinctively coloured. The present international convention is

A. brown for earth, yellow for live, light blue for neutral

B. green for earth, yellow for live, brown for neutral

C. yellow for earth, green for live, brown for neutral

D. brown or red for live, light blue or black for neutral and green or yellow for earth

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The plants in a greenhouse are enclosed in a glass enclosure because

A. glass allows the heat radiations of shorter wavelengths from the sun to pass through

B. the plants absorb them - these shorter wavelengths - and reradiate them in the form of longer wavelengths

C. the longer wavelengths cannot penetrate through the glass walls

D. All the above

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When light passes from air to glass, its velocity in glass

A. increases

B. decreases

C. remains unchanged

D. first decreases then increases

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At temperature near OK, (zero kelvin) metals such as lead and tin become

A. insulators

B. semiconductors

C. superconductors

D. condenser

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When light passes from air to glass, its velocity in glass

A. increases

B. decreases

C. remains unchanged

D. first decreases then increases

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If a body weight 12N on the surface of the earth, how much will it weigh on the surface of the moon where acceleration due to gravity is only one-sixth of that on earth's surface?

A. 12N

B. 2N

C. 10N

D. 6N

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A capillary tube is partially dipped vertically in a vessel containing water. Due to capillarity water rises in the tube. The height of water rise in the tube can be increased by

A. decreasing the radius of the capillary tube

B. increasing the radius of the capillary tube

C. increasing the height of water in the vessel

D. None of these

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A star contains

A. about 75% of hydrogen

B. 22% helium

C. traces of most other elements including oxygen, neon, carbon and nitrogen

D. All the above

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The inside of both the walls of a thermos flask is silvered i.e., on the vacuum side in order to reduce heat loss by

A. convection

B. radiation

C. conduction

D. All the three

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A hunter on the ground wishes to shoot a bird on a tree at a distance with his rifle. He has to point the rifle

A. at the lower elevation than the bird

B. at a higher elevation than the bird

C. in the same direction as the bird

D. vertically upwards

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A hydraulic brake in an automobile uses

A. a fluid to transmit the braking force

B. the force applied by the driver

C. hydrogen gas and not any liquid

D. a vacuum brake

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A piece of cork is embedded inside an ice block which floats in water. What will happen to the level of water when all ice melts?

A. It will go down

B. It will come up

C. It will remain at the same level

D. First it will go down and it will come up

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A spherical mirror is

A. a reflecting elliptical portion

B. a reflecting spherical surface

C. a parabolic reflecting surface

D. a flat reflecting surface

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The SI unit of electric current is

A. the ampere

B. the volt

C. the ohm

D. the coulomb