The frequency of yellow light having wavelength $600 \ nm$ is

Consider two radiations of wavelengths $1. \lambda_1 = 2000 \mathring{A}$ and $2. \lambda_2 = 6000 \mathring{A}$. The ratio of the energies of these two radiations $\left(\frac{E_1}{E_2}\right)$ is . . . . . . (Nearest integer).

$A$ magnet will cause the greatest deflection of

Mercury street lights emit light of a pale blue color with a wavelength of $436 \, nm$. Calculate its frequency.

The frequency of an electromagnetic radiation is $2 \times 10^6 \ Hz$. What is its wavelength in metres? (Velocity of light $= 3 \times 10^8 \ m \ s^{-1}$)

Which of the following does not characterise $X$-rays?