Photons of an electromagnetic radiation have an energy of $11 \, keV$ each. To which region of the electromagnetic spectrum does it belong?

In which one of the following regions of the electromagnetic spectrum will the vibrational motion of molecules give rise to absorption?

$A$ 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 $c = 3 \times 10^8 \text{ m/s}$).

The frequencies of $X$-rays,$\gamma$-rays,and ultraviolet rays are $a, b$,and $c$ respectively. Which of the following relations is correct?

Infrared rays can be detected by .......

Which is the correct ascending order of wavelengths?