The region of the atmosphere above the troposphere is known as:

Arrange the following in the ascending order of wavelength $(\lambda) :$
$(A)$ Microwaves $(\lambda_1)$
$(B)$ Ultraviolet rays $(\lambda_2)$
$(C)$ Infrared rays $(\lambda_3)$
$(D)$ $X-$rays $(\lambda_4)$
Choose the most appropriate answer from the options given below $:-$

Which of the following is an electromagnetic wave?

Arrange the following in the ascending order of wavelength :
$(A)$ Gamma rays $(\lambda_1)$
$(B)$ $X$-rays $(\lambda_2)$
$(C)$ Infrared waves $(\lambda_3)$
$(D)$ Microwaves $(\lambda_4)$
Choose the most appropriate answer from the options given below :

If the frequencies of $X$-rays,$\gamma$-rays,and ultraviolet rays are $a, b$,and $c$ respectively,then which of the following is correct?

$A$ monochromatic source of light operating at $15 \text{ kW}$ emits $2.5 \times 10^{22} \text{ photons/s}$. The region of an electromagnetic spectrum to which the emitted electromagnetic radiation belongs to . . . . . . . (Take $h = 6.6 \times 10^{-34} \text{ J}\cdot\text{s}$ and $c = 3 \times 10^8 \text{ m/s}$).