Ray optics practice · Mixed difficulty

$P$ is a point on the axis of a convex mirror. The image of $P$ formed by the mirror, coincides with $P$. A rectangular glass slab of thickness $t$ and refractive index $\mathrm{\mu }$ is now introduced between $P$ and the mirror. For the image of P to coincide with $P$ again, the mirror must be moves

Two thin lenses of focal length $\mathrm{20}\,\,\mathrm{cm}$ and $\mathrm{25}\,\,\mathrm{cm}$ are placed in contact .The effective power of the combination is

The deviation produced by a prism is

An astronaut in a spaceship see the outer space as

In the position of minimum deviation when a ray of yellow light passes through the prism, then its angle of incidence is

White light is incident on one of the refracting surfaces of a prism of angle $5^\circ$. If the refractive indices for red and blue colours are $\mathrm{1}\mathrm{.641}$ and $\mathrm{1}\mathrm{.659}$ respectively, the angular separation between these two colours when they emerge out of the prism is

If there had been one eye of the man, then

Three prisms $\mathrm{1, 2 }\,\mathrm{and\,3}$ have the prism angle $A = {60^0}$, but their refractive indices are respectively $\mathrm{1}\mathrm{.}\,\mathrm{4, 1}\mathrm{.}\,\mathrm{5 }\,\mathrm{and}\,\mathrm{ 1}\mathrm{.}\,\mathrm{6}$. If ${\delta _1},\,\,{\delta _2},\,\,{\delta _3}$ be their respective angles of deviation then

When a plane mirror is rotated through an angle $\theta$ then the reflected ray turns through the angle $2\,\theta$ then the size of the image

If a thin prism of glass is dipped into water then minimum deviation (with respect to air) of light produced by prism will be left $\left( {_a{\mu _g} = \frac{3}{2}\,\,\mathrm{and}\,{\,_a}{\mu _w} = \frac{4}{3}} \right)$

A short pulse of white light is incident from air to a glass
slab at normal incidence. After travelling through the slab,
the first colour to emerge is

The focal length of plane mirror is :

A plane mirror reflects a beam of light to from a real image. The incident beam is :

A convex lens forms a real image of a point object placed on its principal axis. If the upper half of the lens is painted black, the image will

Assertion: A reflecting type of telescope is preferred over refracting type in astronomy.
Reason: A reflecting type of telescope is free from chromatic aberration and spherical aberration.

A convex lens 'A' of focal length 30 cm and a
concave lens 'B' of focal length 10 cm are kept
along the same axis with a distance 'd' between
them. If a parallel beam of light falling on 'A' leaves
'B' as a parallel beam, then the distance 'd' in cm
will be:

Assertion: If the rays are diverging after emerging from a lens; the lens must be concave.
Reason: The convex lens can give diverging rays.
In above question a statement of assertion is followed by statement of reason mark the correct choice.

Radius of curvature of concave mirror is $40\,\,cm$ and the size of image is twice as that of object, then the object distance is

Assertion: The cloud in sky generally appear to be whitish.

Reason: Diffraction due to cloud is efficient in equal measure at all wavelengths.

Statement-A: The blue colour of sky is on account of scattering of sun light.

Statement-B: The intensity of scattered light varies inversely as the fourth power of wavelength of the light.

Which of the following statements is correct?

Assertion: A ray of light incident along the normal to the plane mirror retraces its path after reflection from the mirror.
Reason: A ray of light along the normal has angle of incidence as $\pi / 2$ and hence, it retraces its own path after reflection from mirror.

If aperture of lens is halved then image will be

The spectrum obtained from an electric lamp or red hot heater is

A person using a lens as a simple microscope sees an

In a convex mirror having radius of curvature $30 \mathrm{~cm}$ the height of image is half the object height. What will be the object (in $\mathrm{cm}$) distance?

The wavelength of light in air and some other medium are respectively ${\lambda _a}$ and ${\lambda _m}$. The refractive index of medium is

The radii of curvature of the faces of a double convex lens are $10 \mathrm{~cm}$ and $15 \mathrm{~cm}$. If focal length is $12 \mathrm{~cm}$, what is the refractive index of glass?

Statement-I: For observing traffic at our back, we prefer to use a convex mirror.

Statement-II: A convex mirror has a much larger field of view than a plane mirror or a concave mirror.

First and second focal lengths of spherical surface of $n$ refractive index are $f_1$ and $f_2$ respectively. The relation between them, is