Ray optics practice · Medium

An eye can distinguish between two points of an object if they are separated by more than $0.22 \mathrm{~mm}$ when the object is placed at $25 \mathrm{~cm}$ from the eye. The object is now seen by a compound microscope having a $20\,\mathrm{D}$ objective and $10\,\mathrm{D}$ eyepiece separated by a distance of $20 \mathrm{~cm}$. The final image is formed at $25 \mathrm{~cm}$ from the eye. What is the minimum separation between two points of the object which can now be distinguished?

An object is viewed through a compound microscope and appears in focus when it is $\mathrm{5 mm}$ away from the objective lens. When a sheet of transparent material $\mathrm{3 mm}$ thick is placed between the objective and the microscope, the objective lens has to be moved $\mathrm{1 mm}$ to bring the object back into the focus. The refractive index of the transparent material is

Under minimum deviation condition in a prism, if a ray is incident at an angle ${30^ \circ }$, the angle between the emergent ray and the second refracting surface of the prism is

A convex lens of glass $(\mu=1.5)$ having focal length ${f}=15 \mathrm{~cm}$ is dipped completely in water. Focal length of convex lens in water becomes $\left(\mu_{\text {water}}=\frac{4}{3}\right)$

${F_1}$ and ${F_2}$ are focal lengths of objective and eyepiece respectively of the telescope. The angular magnification for the given telescope is equal to

The process not involved in the formation of rainbow is

Statement-A: When a white light is passed through a lens, violet light is more refracted than red light.

Statement-B: Focal length for red light is greated than violet.

Which of the following is not the application infra-red waves:

Ray optics is valid, when characteristic dimensions are

When the length of a microscope tube increases, its magnifying power

A thin plano-convex lens acts like a concave mirror of focal length $\mathrm{0}\mathrm{.2 m}$ when silvered from its plane surface. The refractive index of the material of the lens is $\mathrm{1}\mathrm{.5}$. The radius of curvature of the convex surface the lens will be

A thin prism of refracting angle $2^{\circ}$ deviates an incident ray through an angle of $1^{\circ}$. Find the value of refractive index of the material of the prism.

The wavelength of red light from He-Ne laser is $\mathrm{633}\,\,\mathrm{nm}$ in air but $\mathrm{474}\,\,\mathrm{nm}$ in the aqueous humor inside the eye ball. Then the speed of red light through the aqueous humor is

A convex lens of crown glass $\left( {n = 1.525} \right)$ will behave as a divergent lens if immersed in

The radii of curvature of a double convex lens are $10 \mathrm{~cm}$ and $20 \mathrm{~cm}$ respectively. Calculate its focal length when it is immersed in a liquid of refractive index 1.65. State the nature of the lens in the liquid. The refractive index of glass is 1.5 .

If a wave gets refracted into a denser medium, then which of the following is true?

The light gathering power of a camera lens depends on

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

A 2 meter long scale with least count of $0.2 \, \mathrm{cm}$ is used to measure the locations of objects on an optical bench. While measuring the focal length of a convex lens, the object pin and the convex lens are placed at $80 \, \mathrm{cm}$ mark and $1 \, \mathrm{m}$ mark, respectively. The image of the object pin on the other side of lens coincides with image pin that is kept at $180 \, \mathrm{cm}$ mark. The % error in the estimation of focal length is:

The focal length of the objective lens of a compound microscope is

Which of the following colours suffers maximum deviation in a prism

A plane mirror can form

Assertion : the focal length of objective lens in telescope is much more than that of eye piece.

Reason : Telescope has high resolving power due to large focal length.

If the far point of myopic eye is 150 cm, the power of the lens required to correct the defect would be

The focal lengths of convex lens for red and blue light are $100\,\,cm$ and $96.8\,\,cm$ respectively. The dispersive power of material of lens is

Two plane mirrors inclined to each other at an angle ${72^0}$, what is the number of image formed?

A telescope with objective of focal length $60 {~cm}$ and eyepiece of focal length $5 {~cm}$ is focused on a far off distant object such that parallel rays emerge from the eyepiece. If object subtends an angle of $2^{\circ}$ on the objective, angular width of the image will be

The equivalent optical path length of two media in contact of lengths $x_1$ and $x_2$ of refractive index $\mu_1$ and $\mu_2$ respectively, is

Statement I: Glass is transparent but its powder seems
opaque. When water is poured over it, it becomes
transparent.
Statement II: Light gets refracted through water.

The focal length of a simple convex lens used as a magnifier is $\mathrm{10}\,\,\mathrm{cm}$. For the image to be formed at a distance of distinct vision $\left( {D = 25\,\,\mathrm{cm}} \right)$, the object must be placed away from the lens at a distance of