EASY
KEAM
IMPORTANT
Earn 100

Among the following, which is not true for ultraviolet light?
(a)induces the production of more melanin, causing tanning of the skin
(b)can be focused into very narrow beams
(c)kills germs in water purifiers
(d)used in eye surgery.
(e)treatment for certain forms of cancer

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Important Questions on Electromagnetic Waves
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If an electromagnetic wave of frequency travels from vacuum into a dielectric medium of electrical permittivity

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If and are respectively the electrical permittivity and magnetic permeability of vacuum, the dimensional formula for is

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IMPORTANT
The electric field of an electromagnetic wave in free space is given by Which of the following statements is correct ?

MEDIUM
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IMPORTANT
A radio transmitter sends out of radiation. Assuming that the radiation is uniform on a sphere with the transmitter at its centre, the intensity of the wave at a distance is

EASY
KEAM
IMPORTANT
Among the following, which is not true for ultraviolet light?
