Ray optics practice · Mixed difficulty

A small telescope has an objective lens of focal length $150 \mathrm{~cm}$ and eyepiece of focal length $5 \mathrm{~cm}$. What is the magnifying power of the telescope for viewing distant objects in normal adjustment?
If this telescope is used to view a $100 \mathrm{~m}$ tall tower $3 \mathrm{~km}$ away, what is the height of the image of the tower formed by the objective lens?

In which of the following optical instrument, the final image of real object is not inverted?

When monochromatic red light is used instead of blue light in a convex lens, its focal length will

Critical angle of light passing from glass of water is minimum for

Microscope is an optical instrument which

Pick the wrong answer in the context with rainbow.

A thin prism of angle $15^\circ$ made of glass of refractive index ${\mu _1} = 1.5$ is combined with another prism of glass of refractive index ${\mu _2} = 1.75$. The combination of the prisms produces dispersion without deviation. The angle of the second prism should be

A screen is placed $90\, {~cm}$ from an object. The image of an object on the screen is formed by a convex lens at two different locations separated by $20\, {~cm}$. The focal length of the lens is

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

Reason: A convex mirror has a much larger field of viwe than a plane mirror or a concave mirror.

Different objects at different distances are seen by the eye. The parameter that remains constant is

Astigmatism (for a human eye) can be removed by using

A beam of white light is incident on a convex lens. Which of the following is the correct relation between the focal length for red light $\left(f_R\right)$ and that of violet light $\left(f_V\right)$ ?

A ray of light enters a rectangular glass slab of refractive index $\sqrt{3}$ at angle of incidence $60^{\circ}$. It ravels a distance of $10 \mathrm{~cm}$ inside the slab and emerges out of the slab. The perpendicular distance between the incident and the emergent rays is

A slide projector has to project a $35 \mathrm{~mm}$ slide $(35 \mathrm{~mm} \times 23 \mathrm{~mm})$ on a $2 \mathrm{~m} \times 2 \mathrm{~m}$ screen at a distance of $10 \mathrm{~m}$ from the lens. What should be the focal length of the lens in the projector?

From which source a continuous emission spectrum and a line absorption spectrum are simultaneously obtained

In a refracting astronomical telescope, the final image is

A thin glass lens of refractive index 1.5 has optical power of –4 D in air. Its optical power in a liquid medium having refractive index 1.6 will be

Assertion: Angle of deviation depends on the angle of prism.
Reason: For thin prism $\delta=(\mu-1) \mathrm{A}$, Where $\delta=$ angle of deviation $\mu=$ refractive index, $\mathrm{A}=$ angle of prism

A person’s near point is $50\,\,cm$ and his far point is $3\,\,m$. Power of the lenses he requires for
(i) reading and
(ii) for seeing distant stars are

Dispersive power depends upon

Speed of light is maximum in

In a simple microscope, if the final image is located at infinity then its magnifying power is

A light ray, going through a prism with the angle of prism $60^{\circ}$, is found to deviate by $30^{\circ}$. What limit on the refractive index can be put from these data?

If the refractive indices of crown glass for red, yellow and violet colours are $\mathrm{1}\mathrm{.5140, 1}\mathrm{.5170}\,\mathrm{ and }\,\mathrm{1}\mathrm{.5318}$ respectively and for flint glass these are $\mathrm{1}\mathrm{.6434,}\,\,\mathrm{1}\mathrm{.6499}\,\mathrm{ and }\,\mathrm{1}\mathrm{.6852}$ respectively, then the dispersive powers for crown and flint glass are respectively

An achromatic combination of lenses produces

Which of the following is used in optical fibres

On heating a liquid, the refractive index generally

When light travels from one medium to the other of which the refractive index is different, then which of the following will change

Statement-A: The minimum distance between an object and its real image formed by a convex lens is $2{f}$.

Statement-B: The distance between an object and its real image is minimum when its magnification is -1.

A person is suffering from hypermetropia and use lens of +1D if due to ageing its accommodation power also decreases by + 2D. Where will his near point without spects: