Ray optics practice · Medium

An achromatic combination of lenses is formed by joining

Find the angle of refraction in a medium $(\mu=2)$ if light is incident in vacuum, making angle equal to twice the critical angle.

A car is moving with at a constant speed of $60 \,{kmh}^{-1}$ on a straight road. Looking at the rear view mirror, the driver finds that the car following him is at distance of $100 {~m}$ and is approaching with a speed of $5 {~km} {~h}^{-1}$. In order to keep track of the car in the rear, the driver begins to glance alternatively at the rear and side mirror of his car after every $2 {~s}$ till the other car overtakes. If the two cars were maintaining their speeds, which of the following statement (s) is/are correct?

The radii of curvature of a double convex lens of glass $(\mu=1.5)$ are in the ratio $1: 2$. This lens renders the rays parallel coming from an illuminated filament at a distance of $6 \mathrm{~cm}$. Calculate the radii of curvature of its surfaces.

For a prism of refractive index $\mathrm{1}\mathrm{.732}$, the angle of minimum deviation is equal to the angle of prism. Then the angle of the prism is

When a picture drawn on paper is seen through a slab of a transparent material of thickness $5\mathrm{~cm}$, it appears to be raised by $1.5 \mathrm{~cm}$. The critical angle at the boundary of this transparent material and air is

A defective eye cannot see close objects clearly because their image is formed

A glass lens is placed in a medium in which it is found to behave like a glass plate. Refractive index of the medium will be

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

The focal length of objective and eye-piece of a microscope are $\mathrm{1}\,\,\mathrm{cm }\,\mathrm{and}\,\mathrm{ 5}\,\,\mathrm{cm}$ respectively. If the magnifying power for relaxed eye is $45$, then length of the tube is

Monochromatic light is reflected from air into a glass of refractive index $\mu$. The ratio of the wavelength of the incident and refracted waves is

A man is suffering from colour blindness for green colour. To remove this defect, he should use goggles of

An optical fibre $(\mu=1.72)$ is surrounded by a glass coating $(\mu=1.50)$. Find the critical angle for total internal reflection at the fibre-glass interface.

A monochromatic light wave with wavelength $\lambda_{1}$ and frequency $v_{1}$ in air enters another medium. If the angle of incidence and angle of refraction at the interface are $45^{\circ}$ and $30^{\circ}$ respectively, then the wavelength $\lambda_{2}$ and frequency $v_{2}$ of the refracted wave are:

A medium is said to be dispersive, if

At sun rise or sunset, the sun looks more red than at mid-day because

Convergence of concave mirror can be decreased by dipping in

Nature of image of a real object formed by convex mirror is always

A leaf which contains only green pigments, is illuminated by a laser light of wavelength $0.632\,\,\mu m$. It would appear to be

Image of an object approaching a convex mirror of radius of curvature $\mathrm{20}\,\,\mathrm{m}$ along its optical axis is observed to move from $\frac{{25}}{3}\,\,\mathrm{m}$ to $\frac{{50}}{7}\,\,\mathrm{m}$ in $\mathrm{30 s}$. What is the speed of the object in $\mathrm{kmh}{\,^{ - 1}}$ ?

The velocity of light in glass is $2 \times 10^8 \mathrm{~ms}^{-1}$ and that in air is $3 \times 10^8 \mathrm{~ms}^{-1}$. By how much would an ink dot appear to be raised, when covered by a glass plate $6.0 \mathrm{~cm}$ thick?

Sun light falls normally on a surface of area $36 \mathrm{~cm}^2$ and exerts an average force of $7.2 \times 10^{-9} \mathrm{~N}$ within a time period of 20 minutes. Considering a case of complete absorption, the energy flux of incident light is

A microscope is having objective of focal length $1 \mathrm{~cm}$ and eyepiece of focal length $6 \mathrm{~cm}$. If tube length is $30 \mathrm{~cm}$ and image is formed at the least distance of distinct vision, what is the magnification produced by the microscope. (Take $D=25 \mathrm{~cm}$ )

An object is kept at a distance of $\mathrm{16}\,\,\mathrm{cm}$ from a thin lens and the image formed is real. If the object is kept at a distance of $\mathrm{6}\,\,\mathrm{cm}$ from the same lens, the image formed is virtual. If the sizes of the images formed are equal the focal length of the lens will be

Statement-I: The images formed by total internal reflections are much brighter than those formed by mirrors or lenses.

Statement-II: There is no loss of intensity in total internal reflection.

Which of the following statement is true

The image formed by an objective of a compound microscope is

A ray is incident at an angle of incidence i on one surface of a small angle prism (with angle of prism $\mathrm{A}$) and emerges normally from the opposite surface. If the refractive index of the material of the prism is $\mathrm{\mu }$, then the angle
of incidence is nearly equal to:

The ratio of the refractive index of red light to blue light in air is

A bi-convex lens made of glass (refractive index $\mathrm{1}\mathrm{.5}$) is put in a liquid of refractive index $\mathrm{1}\mathrm{.5}$. Its focal length will