- ALasers
- BReactors
- CRadio and television
- DComputer
Explanation:
The communication and broadcasting following the base on generation, propagation, and detection of electromagnetic waves.
The electromagnetic spectrum describes a different range of electromagnetic waves. These EM waves are a special type of wave that can travel without a medium.
Electromagnetic waves are named like this due to the fact that they have both an electric and a magnetic component. In a vacuum, EM waves always travel at the same speed i.e. the speed of light. So, other EM waves besides light are infrared, ultraviolet, radio waves, and microwaves.
Therefore radio and television both are based on EM wave properties. Other options like lasers, reactors, and computers are not guided by EM waves.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
An object is placed at 20 cm from a convex mirror of focal length 10 cm. The image formed by the mirror is
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(a) Real and at 20 cm from the mirror |
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(b) Virtual and at 20 cm from the mirror |
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(c) Virtual and at 20/3 cm from the mirror |
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(d) Real and at 20/3 cm from the mirror |
The optical path of a monochromatic light is same if it goes through 4.0 cm of glass or 4.5 cm of water. If the refractive index of glass is 1.53, the refractive index of the water is
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(a) 1.30 |
(b) 1.36 |
(c) 1.42 |
(d) 1.46 |
Assertion : Faraday’s laws are consequences of conservation of energy.
Reason : In a purely resistive ac circuit, the current lags behind the e.m.f. in phase.
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
If rotational velocity of a dynamo armature is doubled, then induced e.m.f. will become
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(a) Half |
(b) Two times |
(c) Four times |
(d) Unchanged |
In the circuit shown in the figure, the potential difference across the 4.5mF capacitor is

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(a) |
(b) 4 volts |
(c) 6 volts |
(d) 8 volts |
In Young's double slit experiment, if L is the distance between the slits and the screen upon which interference pattern is observed, x is the average distance between the adjacent fringes and d being the slit separation. The wavelength of light is given by
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(a) |
(b) |
(c) |
(d) |