Lens Formula and Magnification

Q.

Linear magnification of a mirror has no units.

1. True
2. False

Q. A point object is placed at a distance of $25cm$ from a convex lens of focal length $20cm$. If a glass slab of thickness $t$ and $R.I.1.5$ is inserted between the lens and the object, the image is formed at infinity. The thickness $t$ of the glass slab is

1. $15cm$
2. $5cm$
3. $10cm$
4. $20cm$

Q. An object is kept at $15cm$ from a convex mirror of focal length $25cm$. Calculate the image distance.

1. $9.37cm$ behind the mirror
2. $9.3cm$ in front of the mirror
3. Insufficient data
4. $15cm$ behind the mirror

Q. An object $ABED$ is placed in front of a concave mirror beyond the center of curvature $C$ as shown in Fig. State the shape of the image.

1. $|m_{AB}|<1$ and $|m_{ED}|<1$
2. $|m_{AB}|<1$ and $|m_{ED}|>1$
3. $|m_{AB}|>1$ and $|m_{ED}|<1$
4. $|m_{AB}|>1$ and $|m_{ED}|>1$

Q. Which of the following mirror has the widest field of view?

1. Plane mirror
2. Concave mirror
3. Convex mirror
4. Plane and concave mirror

Q. An object of height 5 cm is placed at 30 cm distance on the principal axis infront of a concave mirror of focal length 20 cm. Find the image distance and size of the image.

Q. Object is placed on the principal axis of a concave mirror. Its real image is formed at a point which is 10 cm more distant from the mirror than the object. If focal length of mirror 12 cm. The magnitude of magnification of the image is:

1. 1
2. 2.5
3. 1.5
4. 2

Q.

OA is an object with object size $4cm$ and O'A' is the image of the object. If the distance of object and image from the optical center is 30cm and 15cm respectively. Find the height of the image formed.

1. $4cm$

2. $2cm$

3. $3cm$

4. $3cm$

Q. An object is kept at a distance of $16cm$ from a thin lens and the image formed is real. If the object is kept at a distance of $6cm$ from the same lens, the image formed is virtual. If the sizes, of the images formed are equal, the focal length of the lens will be

1. $15cm$
2. $17cm$
3. $21cm$
4. $11cm$

Q. Which of the following mirror has the widest field of view?

1. Convex mirror
2. Plane and concave mirror
3. Concave mirror
4. Plane mirror

Q. A convex mirror has a radius of curvature of $20cm$. An object is placed at such a distance from the mirror that the size of the image is exactly half that of the object. The object distance must be :

1. $20cm$
2. $30cm$
3. $10cm$
4. $40cm$

Q. Which of the following mirror has the widest field of view?

1. Concave mirror
2. Plane mirror
3. Convex mirror
4. Plane and concave mirror