Ray optics practice · Mixed difficulty

An object approaches a converging lens from the left of
the lens with a uniform speed 5 m/s and stops at the
focus. The image

A convex glass lens $\left( {{\mu _g} = 1.5} \right)$ has a focal length of 8 cm when placed in air. What is the focal length of the lens when it is immersed in water $\left( {{\mu _g} = \frac{4}{3}} \right)$

The radius of curvature of each surface of a convex lens of refractive index 1.5 is $40 \mathrm{~cm}$. Calculate its power.

Near and far points of human eye are

Assertion: We cannot produce a real image by plane or convex mirrors under any circumstances.
Reason: The focal length of a convex mirror is always taken negative.

Given below are two statements:
Statement (I): When an object is placed at the centre of curvature of a concave lens, image is formed at the centre of curvature of the lens on the other side.
Statement (II): Concave lens always forms a virtual and erect image.
In the light of the above statements, choose the correct answer from the options given below:

The condition for an achromatic doublet, is (${f_1}\,\,{\text{and }}{f_2}$ are the focal lengths of individual lenses)

A beam of light converges towards a point $O, 10$ $\,{cm}$ behind a concave mirror of focal length 20 $\,{cm}$. Magnification produced by the mirror is

When light is passed through a prism, the colour which deviates least is -

A source of light lies on the angle bisector of two plane mirrors inclined at angle $\theta$. The values of $\theta$, so that the light reflected from one mirror does not reach the other mirror will be

An experiment is performed to find the refractive index of glass using a travelling microscope. In this experiment distances are measured by

Assertion: A double convex lens $(\mu=1.5)$ has focal length $10 \mathrm{~cm}$. When the lens is immersed in water $(\mu=4 / 3)$ its focal length becomes $40 \mathrm{~cm}$.
Reason: $\frac{1}{f}=\frac{\mu_1-\mu_m}{\mu_m}\left(\frac{1}{R_1}-\frac{1}{R_2}\right)$

The angular magnification of a simple microscope can be increased by increasing

An object is placed in front of a convex mirror of focal length $f$. Find the maximum and minimum distance of two object from the mirror such that the image is real and magnified.

Two plane mirrors are at right angles to each other. A man stands between them and combs his hair with his right hand. In how many of the images will he be seen using his right hand

A divergent lens will produce

A liquid wets a solid. The meniscus of the liquid in a long vertical capillary tube of that solid is

A thin sheet of glass $(\mu=1.5)$ of thickness 6 microns introduced in the path of one of interfering beams in a double slit experiment shifts the central fringe to a position previously occupied by fifth dark fringe. Then the wavelength of light used is:

Which of the following quantity remains unchanged after refraction?

The focal lengths of the objective and eyelenses of a microscope are $\mathrm{1}\mathrm{.6 }\,\mathrm{cm}$ and $\mathrm{2}\mathrm{.5 }\,\mathrm{cm}$ respectively. The distance between the two lenses is $\mathrm{21}\mathrm{.7 }\,\mathrm{cm}$. If the final image is formed at infinity, the distance between the object and the objective lens is

The refractive indices of water and glass with respect to air are $4 / 3$ and $5 / 3$, respectively. The refractive index of glass with respect to water will be

Sam is standing in front of a reflecting surface and he observes that his image formed by the surface is virtual, erect and magnified. The reflecting surface is a;

If the angle of minimum deviation is ${60^0}$ for an equilateral prism, then the refractive index of the material of the prism is

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

A convex lens made of material of
refractive index 1.5 and having a focal length of
10 cm is immersed in a liquid of refractive index
3.0. The lens will behave as

Critical angle of incidence for a pair of optical media is $45^{\circ}$. The refractive indices of first and second media are in the ratio:

When sunlight is scattered by atmospheric atoms and molecules, the amount of scattering of light of wavelength $\mathrm{440}\,\,\mathrm{nm}$ is $A$. The amount of scattering for the light of wavelength $\mathrm{660}\,\,\mathrm{nm}$ is approximately

With a concave mirror, an object is placed at a distance ${x_1}$ from the principal focus, on the principal axis. The image is formed at a distance ${x_2}$ from the principal focus. The focal length of the mirror is

By taking large aperture objective in telescope
helps in

Focal length of a convex lens will be maximum for