Snakes can detect which type of waves?

The following table presents parts of the electromagnetic spectrum and their corresponding major applications.

Part of the electromagnetic spectrum	Applications
$P$. Microwave	$I$. For purifying the water
$Q$. $UV$ rays	$II$. For warming the food
$R$. Gamma rays	$III$. For $AM$ and $FM$ communication systems
$S$. Radio wave	$IV$. For treating the cancer cells

The correct option is:

If $\lambda_r$,$\lambda_v$,and $\lambda_x$ are the wavelengths of red light,violet light,and $X$-rays respectively,then which of the following relations is correct?

Which of the following electromagnetic waves has the longest wavelength?

What is the approximate wavelength range of the electromagnetic spectrum?

The magnetic field in a plane electromagnetic wave is given by $B = 2 \times 10^{-7} \sin(0.5 \times 10^3 x + 1.5 \times 10^{11} t)$. This electromagnetic wave is .........