Question

The frequencies of X-rays, gamma rays and visible light waves rays are a, b and c respectively, then
(A) $a < b, b > c$
(B) $a < b, b < c$
(C) $a > b > c$
(D) $a > b, b < c$

Answer 1

Hint: The frequency of x-rays, $\gamma $-rays and visible light waves are fixed and experimentally calculated by formula $f = \dfrac{c}{\lambda }$
Where f $ = $ frequency of wave
c $ = $ speed of light
$\lambda = $ wavelength of wave

Complete step by step solution:
X-rays are electromagnetic radiation and its wavelength experimentally given as
$a = 3 \times {10^{19}}$ to $1 \times {10^{16}}$ …..(1)
$\gamma $-rays are also the part of electromagnetic radiation & its wavelength range is given by
$b = 3 \times {10^{22}}$ to $3 \times {10^{18}}$ …..(2)
Visible light waves are also the part of electromagnetic waves & its wavelength the range is given as
$c = 8 \times {10^{14}}$ to $4 \times {10^{14}}$ …..(3)
On comparing equation (1), (2) & (3) we get
$\boxed{b > a, b > c}$

Hence option A is correct.

Note: There are many other types of radiation present in the electromagnetic wave spectrum which are infra-red radiation, microwaves, radio waves, $\gamma $-rays, x-rays, visible rays, ultra-violet etc.