$A$ laser beam is used for surgery because it can be...

$A$ source emits light of wavelengths $4700 \ \mathring{A}$,$5400 \ \mathring{A}$,and $6500 \ \mathring{A}$. The light passes through red glass before being tested by a spectrometer. Which wavelength is seen in the spectrum?

$A$ source of light emits a continuous stream of light energy which falls on a given area. Luminous intensity is defined as

In the given figure,light of intensity $I$ is incident on a glass slab at point $A$ at an angle of incidence $\theta_1$. It undergoes partial reflection and partial refraction. At each reflection,$25\%$ of the incident energy is reflected. If interference occurs between the rays $AB$ and $A'B'$,then $I_{max}/I_{min} = \dots$ (in $: 1$)

The difference in the number of wavelengths,when yellow light propagates through air and vacuum columns of the same thickness,is one. Find the thickness of the air column. Given: Refractive index of air $\mu_a = 1.0003$,Wavelength of yellow light in vacuum $\lambda_0 = 6000 \text{ Å}$.

The relative luminosity of wavelength $600 \,nm$ is $0.6$. Find the radiant flux of $600 \,nm$ needed to produce the same brightness sensation as produced by $120 \,W$ of radiant flux at $555 \,nm$.