What are called heat waves?

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

The frequencies of $\gamma$-rays,$X$-rays,and ultraviolet radiations are $B, A,$ and $C$ respectively. Which of the following relations is correct?

The frequency of a wave is $6 \times 10^{15} \text{ Hz}$. This wave is:

The frequency range from $3\, MHz$ to $30\, MHz$ is known as:

Which of the following is absorbed by the ozone layer?