Level 2

It is desired to photograph the image of an object placed at a distance of $3 \mathrm{m}$ from a plane mirror. The camera, which is at a distance of $4.5 \mathrm{m}$ from the mirror should be focused for a distance of-

A long horizontal mirror is next to a vertical screen (see figure). Parallel light rays are falling on the mirror at an angle $\alpha$ from the vertical. If a vertical object of height $h$ is kept on the mirror at a distance $d>h$ $\tan \left(\alpha \right).$ The length of the shadow of the object on the screen would be.

Three rays of light, namely red $\left(R\right)$, green $\left(G\right)$ and blue $\left(B\right)$ are incident on the face $PQ$ of a right angled prism $PQR$ as shown in figure.

The refractive indices of the material of the prism for red, green and blue wavelength are $1.27,1.42$ and $1.49$ respectively. The colour of the ray(s) emerging out of the face $PR$ is :

A ray of light passes from a denser medium to a rarer medium at an angle of incidence $i.$ The reflected and refracted rays make an angle of $90°$ with each other. The angle of reflection and refraction are respectively $r$ and $r^{\text{'}}.$ The critical angle is given by,

A ray of laser of a wavelength $630 \mathrm{nm}$ is incident at an angle of $30°$ at the diamond-air interface. It is going from diamond to air. The refractive index of diamond is $2.42$ and that of air is $1$. Choose the correct option.

The radii of curvature of the spherical surfaces of a biconvex lens are $20 \mathrm{cm}$ and $30 \mathrm{cm}$. The refractive index of the material of the lens is $1.65$. If the lens is submerged in a liquid of refractive index $1.1$, its effective focal length will be

If the focal length of the biconvex lens is $25 \mathrm{cm}$, then the power is,

Focal length, radius of curvature and power of a plane mirror respectively are