Wait for the laser in dark

Laser is/ are

An equilateral glass prism kept on a table has refractive index of mu = sqrt(2) . It is illuminated by a narrow laser beam having power P_(0) and wavelength l. The path of the laser beam inside the prism is parallel to the base of the prism. Calculate change in weight of the prism due to the incident laser beam.

The conditions for achieving laser action are

In Young's experiment if the dark bands are to be perfectly dark, then

What is a laser ?

What is the basis of laser action?

A laser operates at a frequency of 5 xx 10^(14) Hz . If the laser has an aperture of 10 mm, what will be the angular spread?

Can we use laser in thermonuclear reactions?

Why should we not view the lasers directly?