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Current Affairs January 2024

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4

The overhead wires supported by high towers in the grid system carry

A. alternating current of very high frequency

B. alternating current of very high voltage

C. a very large direct current

D. a high voltage direct current

Correct Answer :

B. alternating current of very high voltage


Related Questions

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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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4

On applying a constant force to a mass, It moves with a uniform

A. velocity

B. momentum

C. acceleration

D. angular velocity

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4

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

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4

Less dew is formed on cloudy nights because

A. there is no moisture in the atmosphere

B. clouds absorb the falling dew

C. objects emit radiant energy very fast on such nights

D. objects lose less radiant energy

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4

Match the following:
A. Manometer1. Depth of sea
B. Audiometer2. High temperatures
C. Pyrometer3. Level of human hearing
D. Fathometer4. Pressure of a gas

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

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

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

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

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4

A thermostat is a device used

A. for automatically maintaining a steady temperature

B. for measuring electricity

C. to reduce the voltage of electricity

D. for producing heat

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4

When light travels from one medium to another there is a change in its

A. velocity

B. wavelength

C. frequency

D. Both (a) and (b) above

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4

In compact porous soil, the rising of the water is due to

A. capillarity

B. cohesion

C. adhesion

D. viscosity

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4

Photoelectric cell is a device which converts

A. light energy into electrical energy

B. electrical energy into light energy

C. magnetic energy into electrical energy

D. electrical energy into mechanical energy

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4

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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4

A tube light works on the principle of

A. chemical, heating and magnetic effects of electricity

B. discharge of electricity through gases

C. the action of ultraviolet radiation on certain fluorescent materials

D. Both (b) and (c) above

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4

Choose the correct answer

A. Microphone converts sound energy into electrical energy.

B. Electric fan converts electrical energy into mechanical energy.

C. Battery converts chemical energy into electrical energy.

D. All the above

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4

Photocells are used

A. in burglar alarms

B. in automotive devices for light switches

C. television cameras

D. All the above

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4

The speed of light is minimum while passing through

A. air

B. glass

C. vacuum

D. water

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4

In the fuse of an electrical installation blows out

A. replace the fuse by a thin wire

B. replace the fuse by a thick copper wire

C. replace the fuse by a fuse wire of proper rating

D. replace the fuse by nichrome wire

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An electric kettle used for boiling hard water has a white scale deposited on its heating element. This consists or

A. sugar

B. sodium carbonate

C. common salt

D. carbonates of calcium and magnesium

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4

Which physical quantity is measured in watts

A. power

B. kinetic energy

C. momentum

D. impulse

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Which of the following wires of same dimensions offers least resistance to the ,flow of current?

A. copper

B. aluminium

C. silver

D. nichrome

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Mercury is used in a barometer because

A. its density being very high 13.6 g/cm3 the height of mercury column is conveniently small

B. at the ordinary temperature its vapour pressure is small

C. it is opaque and does not wet glass

D. All the above

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4

A bolometer is used to measure

A. the quantity of heat energy in a body

B. thermal radiations quantitatively

C. high temperature

D. the intensity of sound

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4

A timer in a race is at the finish line. He should start his stop watch

A. as soon as he hears the report of the gun

B. the moment he sees the flash

C. either (a) or (b) since that makes no difference

D. None of the above

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4

Lightning conductors are made of

A. iron

B. chromium

C. copper

D. steel

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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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4

When sound waves travel from one medium to another, the quantity which remains unchanged is its

A. speed

B. frequency

C. wavelength

D. All the above

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A radio set that uses valves does not start operating immediately when it is switched on whereas a set containing only tranaistors operates immediately. The reason for this is that

A. the valve filaments have low resistance

B. valve-radio sets work at a higher voltage

C. transistor set has a low resistance

D. filaments of the valves cake time to beat up and function

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4

The source of electric energy in an artificial satellite is

A. mininuclear reactor

B. a dynamo

C. a thermopile

D. solar cells

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4

Which of the following has the highest refractive index?

A. Crown glass

B. Water

C. Flint glass

D. Diamond

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Isotones are species of atoms containing

A. same number of protons but different number of neutrons

B. same number of neutrons but different number of protons

C. the same total number of protons and neutrons

D. same number of protons and different number of electrons

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4

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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4

A lightning conductor installed in a building

A. does not allow the lightning to fall on the building at all

B. drives away the charged clouds

C. forces the lightning to fall on other buildings near that building

D. conducts the electric charges to the ground when lightning strikes the building