Ray optics practice · Mixed difficulty

The focal length $\left( f \right)$ of a spherical (concave or convex) mirror of radius of curvature $R$ is

Optical fiber communication is generally preferred over general communication system because

A convex and a concave lens separated by distance dare then put in contact. The focal length of the combination

Two lenses, one concave and the other convex of same power are placed such that their principal axes coincide. If the separation between the lenses is $x$, then

The total distance travelled by light in one year is known as

A convex mirror has a radius of curvature of $20 \mathrm{~cm}$. An object is placed at such a distance from the mirror that the size of the image is exactly half that of the object. The object distance must be:

Two lenses having ${f_1}:{f_2} = 2:3$ has combination to make no dispersion. Find the ratio of dispersive power of glasses used

An astronomical refracting telescope is being
used by an observer to observe planets in
normal adjustment. The focal lengths of the
objective and eye piece used in the
construction of the telescope are 20 m and
2 cm respectively. Consider the following
statements about the telescope:
(a) The distance between the objective and
eyepiece is 20.02 m.

(b) The magnification of the telescope is (–) 1000.

(c) The image of the planet is erect and diminished.

(d) The aperture of eye piece is smaller than that of objective.

The correct statements are:

Magnification at least distance of distinct vision of a simple microscope having its focal length $\mathrm{5 cm}$ is

A lamp is hanging at a height of $4\,\,m$ above a table. The lamp is lowered by $1\,\,m$. The percentage increase in illuminance will be

Image formed by a convex mirror is

The dispersive power of crown and flint glasses are 0.02 and 0.04 respectively. What is the focal length of a convex lens of crown glass which makes an achromatic doublet with a concave lens of flint glass of focal length $80 \mathrm{~cm}?$

Spherical aberration of a plano-convex lens can be minimised:

The field of view is maximum for

A beam of light of width $t$ is incident on an air-water boundary at an angle of incidence $45^{\circ}$. The width of the beam in water is (Refractive index of water $=\mu$):

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.

The frequency of light in air is $5\,\, \times \,\,{10^{14}}\,\,\mathrm{Hz}$. What will be the frequency of light, when it enters in the water?

The length of the optical path of two media in contact of length $d_1$ and $d_2$ of refractive index $\mu_1$ and $\mu_2$ respectively, is

The far point of a myopia eye is at 40 cm. For removing this defect, the power of lens required will be

The focal length of a concave mirror is ${f}$. An object is placed at a distance ${x}$ from the focus an forms a real image. Therefore, the magnification (numerically) is

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?

A ray of light is incidenting normally on a plane mirror. The angle of reflection will be

A circular disc of which $\mathrm{2}\,\mathrm{/}\,\mathrm{3}$ part is coated with yellow and $\mathrm{1}\,\mathrm{/}\,\mathrm{3}$ part is with blue. It is rotated about its central axis with high velocity, then it will be seen as

The focal length of plane mirror is :

A thin equiconvex lens of refractive index $\mathrm{3}\,\mathrm{/}\,\mathrm{2}$ and radius of curvature $\mathrm{30}\,\,\mathrm{m}$ is put in water (refractive index $= \frac{4}{3}\,)$. Its focal length is

An air bubble in a glass slab $(\mu=1.5)$ is $6 \mathrm{~cm}$ deep as viewed from one face and $4 \mathrm{~cm}$ deep as viewed from the other face. The thickness of the glass slab is

Consider an equiconvex lens of radius of curvature $R$ and focal length $f$. If $f > R$, the refractive index $\mu$ of the material of the lens

A person $\mathrm{6}\,\,\mathrm{feet}$ in length can see his full size erect image in a mirror $\mathrm{2}\,\,\mathrm{feet}$ in length. This mirror has to be

Transmission of light to large distances through optical fibres is based on

If in compound microscope ${m_1}$ and ${m_2}$ be the linear magnification of the objective lens and eye lens respectively, then magnifying power of the compound microscope will be