1 Marks Question

Question 11 Mark

Name the electromagnetic waves which :
(a) are useful in removing tension in musceles.
(b) are absorbed by ozone layer in atmosphere.

Answer

(a) Infrared radiation which are known as heat radiations also.
(b) Ultraviolet radiations.

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Question 21 Mark

In which regions of electromagnetic spectrum, the following wavelengths lies ?
(a) 1 $\mu$m, (b) 6563 $\unicode{x212B}$, (c) 820 $\unicode{x212B}$, (d) 1 $\unicode{x212B}$

Answer

(a) Microwave region, (b) Visible region
(c) Infrared region , (d) X-rays region.

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Question 31 Mark

The amplitude of electric field in a plane electromagnetic wave is $E_{0}=150~N/C$ and its frequency is $v=50$ MHz. Calculate the value of oscillating magnetic field $B_{0}$ and angular frequency $\omega$.

Answer

$B_{0}=\frac{E_{0}}{c}=\frac{150N/C}{3\times10^{8}m/s}=5\times10^{-7}T$
$\omega=2\pi v=2\times3.14\times50\times10^{6}r/s$
$=3.14\times10^{8}r/s$

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Question 41 Mark

Name the constituent radiation of electromagnetic spectrum which :
(a) is absorbed by ozone layer in atmosphere.
(b) is produced by striking the electrons of high velocity on metal target.
(c) is used in satellite communication.
(d) has its wavelength range between 400 nm - 700 nm.

Answer

(a) Ultraviolet Radiation, (b) X-rays, (c) Micro waves, (d) Visible light.

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