A laser beam is for locating distant objects because

Q. In a Young's double slit experiment a monochromatic laser beam is used to provide the coherent source. To emit the monochromatic laser beam electron has to jump through an energy band of energy difference $4.2eV$ inside the laser. The wavelength of the laser beam emitted by the laser source is ___ $\dot{A}$.

Q.

A laser beam is used for carrying out surgery, because it

Q. Which of the following statements is not true for a beam of LASER ?

Q. A LASER is a source of very intense, monochromatic, and unidirectional beam oflight. These properties of a laser light can be exploited to measure long distances.The distance of the Moon from the Earth has been already determined very preciselyusing a laser as a source of light. A laser light beamed at the Moon takes 2.56 s to return after reflection at the Moons surface. How much is the radius of the lunar orbit around the Earth ?

Q. A laser operates at a frequency of $3\times {10}^{14}{H}_z$ and has an aperture of $1cm$. The radii spread of the beam is