What is the magnification produced by a plane mirror?

When do an object and its image coincide in a convergent mirror?

What type of lens is an air bubble inside water?

Which kind of mirrors are used in the headlights of a motorcar and why?

What is the value of ₁n₂ × ₂n₁?

The velocity of light in water is times the velocity of light in vacuum. Find the refractive index of water.

What is the distance between the image and the plane mirror, if the object is at 15 m?

How can we find the (rough) focal length of a concave mirror?

A concave mirror of focal length 1.5m forms an image of an object placed at a distance of 40cm. Find the position and nature of the image.

A person wants to see the full length image of tall building in a small mirror. Which type of mirror is used by him?

Why do we not see the actual depth of a lake?

The refractive indices of water and glass are and respectively. Write the relation and find the value of refractive index of water with respect to glass and glass with respect to water.

A concave mirror and a convex lens are held separately in water. What changes, if any, do you expect in the focal length of either?

Redraw the following diagrams given below in your answer book and show the direction of the light ray after refraction from the lens.

A convergent lens has a focal length of 15 cm. At what distance should an object from the optical centre of the lens be placed so that its real image is formed at 30 cm on the other side of the lens?

An object is placed between infinity and the pole of a convex mirror. Draw a ray diagram and also state the position, the relative size and the nature of the image formed.

Draw the ray diagram and also state the position, relative size and nature of the image formed by a concave mirror when the object is placed between its centre of curvature, C and the focus, F.

Define ‘refractive index of a transparent medium.’ What is its unit? Which has a higher refractive index, glass or water?

The image of a candle flame placed at a distance of 45 cm from a spherical lens is formed on a screen placed at a distance of 90 cm from the lens. Identify the type of lens and calculate its focal length. If the height of the flame is 2 cm, find the height of its image.

An object 2 cm in size is placed 30cm in front of a concave mirror of focal length 15cm. At what distance from the mirror should a screen be placed in order to obtain a sharp image? What will be the nature and the size of the image formed? Draw a ray diagram to show the formation of the image in this case.

A convex lens has a focal length of 10 cm. At what distance from the lens should the object be placed so that it forms a real and inverted image 20 cm away from the lens? What would be the size of the image formed if the object is 2 cm high? With the help of a ray diagram show the formation of the image by the lens in this case.

A concave lens has focal length of 20 cm. At what distance from the lens a 5 cm tall object be placed so that it forms an image at 15 cm from the lens? Also calculate the size of the image formed.

What is meant by power of a lens? Name and define its S.I. unit.

One student uses a lens of focal length +50 cm and another of –50cm. State the nature and find the power of each lens. Which of the two lenses will always give a virtual, erect and diminished image irrespective of the position of the object?

A 5 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 18 cm at a distance of 12 cm from it. Use lens formula to determine the position, size and nature to the image formed.

What is meant by ‘power of a lens’?

State and define the S.I. unit of power of a lens.

A convex lens of focal length 25 cm and a concave lens of focal length 10 cm are placed in close focal contact with each other. Calculate the lens power of this combination.

With the help of a ray diagram, state the meaning of refraction of light. State Snell’s law of refraction of light and also express it mathematically.

The refractive index of water with respect to vacuum is and refractive index of vacuum with respect to glass is . If the speed the speed of light in glass is 2 × 10⁸ ms^-1, find the speed of light in (i) vacuum, (ii) water.

With the help of a ray diagram explain why a concave lens diverges the rays of a parallel beam of light.

A 2.0 cm tall object is place perpendicular to the principal axis of a concave lens of focal length 15 cm. At what distance from the lens, should the object be placed so that it forms an image 10 cm from the lens? Also find the nature and the size of image formed.

Draw the ray diagram in each case to show the position and nature of the image formed when the object is placed:

At the centre of curvature of a concave mirror

Draw the ray diagram in each case to show the position and nature of the image formed when the object is placed:

Between the pole P and focus F of a concave mirror

Draw the ray diagram in each case to show the position and nature of the image formed when the object is placed:

In front of a convex mirror

Draw the ray diagram in each case to show the position and nature of the image formed when the object is placed:

At 2f of a convex lens

Draw the ray diagram in each case to show the position and nature of the image formed when the object is placed:

In front of a concave lens