Q.

A doctor has prescribed a corrective lens of power +1.5 D to a patient. Find the focal length of the lens in centimeter. Is the prescribed lens diverging or converging?

Q. We wish to obtain an erect image of an object, using a concave mirror of focal length 15 cm. What should be the range of distance of the object from the mirror? What is the nature of the image? Is the image larger or smaller than the object? Draw a ray diagram to show the image formation in this case.

Q. A spherical mirror and a thin spherical lens have each a focal length of $-15$ cm. The mirror and lens are likely to be :

1. both concave
2. the mirror is concave and lens is convex
3. both Convex
4. the mirror is convex but lens is concave

Q. The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should be the position of the object?

1. Between the principal focus and centre of curvature
2. At the centre of curvature
3. Between the pole of mirror and its principal focus
4. Beyond the centre of curvature

Q. Find the focal length of a lens of power (-2.0)D. What type of lens is this?

Q. An object $5.0cm$ in length is placed at a distance of $20cm$ in front of a convex mirror of radius of curvature $30cm$. Find the position of the image, its nature, and its size.

Q. Where should an object be placed in front of convex lens to get a real image of the size of the object?

1. At the principal focus of the lens
2. At twice the focal length
3. At infinity
4. Between the optical centre of the lens and its principal focus

Q. A concave lens of focal length 15cm forms an image 10 cm from the lens . How far is the object placed from the lens? Draw the ray diagram.

Q. Which of the following lenses would you prefer to use while reading small letters found in a dictionary?

1. A concave lens of focal length of 50 cm
2. A convex lens of focal length of 50 cm
3. A convex lens of focal length of 5 cm
4. A concave lens of focal length of 5 cm

Q. An object $5cm$ in length is held $25cm$ away from converging lens of focal length $10cm$. Draw the ray diagram and find the position, size and nature of the image formed.

Q.

An object of size $7.0cm$ is placed at $27cm$ in front of a concave mirror of focal length $18cm$. At what distance from the mirror should a screen be placed so that a sharp focused image can be obtained? Find the size and nature of the image.

Q. One-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Verify your answers experimentally. Explain your observations.

Q. An object is placed at a distance of 10 cm from a convex mirror of focal length 15 cm. Find the position and nature of the image.