Magnification

Q.

What is the magnification of a plane mirror?

1. $1$

2. $0$

3. $2$

4. $-1$

Q.

Where should an object be placed from a converging lens of the focal length of $20\mathrm{cm}$, so as to obtain a real image of magnification $2$?

Q. An object of height 6 cm is placed on the principal axis of a concave mirror of focal length f at a distance of 4f. The length of the image will be

Q. Magnification is also defined as the of image distance and object distance.

1. product
2. ratio
3. sum

Q. The magnification produced by a plane mirror is ___.

1. 2
2. 1
3. Infinite
4. 0

Q. An object of height 5 cm is placed at a distance of 20 cm from a spherical mirror. If an image is obtained on a screen placed at a distance of 40 cm from the mirror, then what will be its height?

1. 10 cm
2. 20 cm
3. 30 cm
4. 5 cm

Q.

A 3 cm high object is placed at a distance of 80 cm from a concave lens of focal length 20 cm. Find the position and size of the image.

1. 0.1 cm

2. 0.4 cm

3. 0.2 cm

4. 0.6 cm

Q.

What information about the nature of image (i) real or virtual, (ii) erect or inverted, do you get from the sign of magnification + or - ?

Q. Magnification is positive in case of image.

1. real
2. erect
3. inverted

Q. What is the magnification in the given diagram?

Given, OA = 10 cm and O’A’ = 2 cm

1. 5
2. -2
3. - 0.2
4. - 10

Q. An object is placed at 30.0 cm in front of a converging lens. The lens has a focal length of 10.0 cm. What are the values of the image distance and magnification respectively?​

1. 15.0 cm and 2.0
2. 60.0 cm and -0.5
3. 15.0 cm and -0.5
4. 60.0 cm and 2.0

Q.

When the image is of double size as the object, the magnification is

1. three

2. four

3. two

4. one

Q. An object is placed $15cm$ in front of a lens. The lens forms a real image three times magnified. Find out the image distance and the focal length of a lens?

1. $v=35cm$
   $f=13.25cm$
2. $v=45cm$
   $f=11.25cm$
3. $v=-35cm$
   $f=-13.25cm$
4. $v=-45cm$
   $f=11.25cm$

Q.

A convex lens of power 5D is placed at a distance of 30 cm from a screen. At what distance from the lens should the screen be placed so that its image is formed on the screen? [3 MARKS]

Q. A positive sign in the value of magnification indicates that the image is _______.

1. real
2. virtual
3. enlarged
4. near

Q. The linear magnification produced by spherical mirrors is +3. Analyse this value and state the (i) type of mirror and (ii) Position of the object with respect to the pole of the mirror. Draw ray diagram to show the formation of image in this case.

Q. A movie camera with a lens of focal length 75 mm takes a picture of a 180 cm tall person standing 25 m away. What is the height of the image of the person on the film? (Assume the distance of the person from camera to be very large as compared to its focal length)​

1. 2.7 mm
2. 5.4 mm
3. 10.8 mm
4. 16.2 mm

Q. What is the quality of image formed if its magnification is zero

Q.

What is magnification in the below diagram?

If OA = 10 cm and O’A’ = 2 cm?

1. 8

2. 1

3. 

4. 

Q. The magnification of an inverted image is positive.

1. True
2. False

Q. The height of an image and an object is h’ and h, respectively. The magnification will be .

1. h’x h
2. h’/h
3. h/h’

Q.

What is magnification in the below diagram?

If OA = 10 cm and O’A’ = 2 cm?

1. 1

2. 

3. 8

4. 

Q. Magnification of the concave lens is:

1. Less than 1
2. Equal to 1
3. More than 1
4. More than 1 and less than 2

Q.

The magnification formula is?

1. $\frac{heightoftheobject}{heightoftheimage}$

2. $\frac{heightoftheimage}{heightofthelens}$

3. $\frac{heightoftheimage}{heightoftheobject}$

4. $\frac{heightofthemirror}{heightoftheimage}$

Q.

How will the magnitude of magnification change if an object placed at center of curvature of a concave mirror is moved towards focus in the case of a concave mirror?

1. Decreases

2. Increases

3. Magnification becomes zero

4. Remains constant

Q.

When an object of height 3 cm is placed at a distance of 30 cm from a lens, a real image is formed at a distance of 60 cm. Find out the height of the image?

1. -6 cm

2. +6 cm

3. -3 cm

4. +3 cm

Q. An illuminated bulb and a screen are placed $90cm$ apart. What is the focal length of the lens required to produce a real image twice the size of object, on the screen?

1. $f=-20cm$
2. $f=-10cm$
3. $f=20cm$
4. $f=10cm$

Q. A positive sign in the value of magnification indicates that the image is _______.

1. real
2. virtual
3. enlarged
4. near

Q. An object 4 cm in size, is placed 25 cm in front of a concave mirror of focal length 15 cm. At what
distance from the mirror should a screen be placed in order to obtain a sharp image ? Find the nature
and the size of the image.

Q. Match the following options of List I with the appropriate answers in the List II.

List I	List II
P. Negative Magnification	1. Diminsihed Image
Q. Magnification < 1	2. Inverted Image
R. Positive Magnification	3. Size of image is same
S. Magnification = 1	4. Erect image

1. P-1 Q-2 R-3 S-4
2. P-2 Q-1 R-4 S-3
3. P-2 Q-3 R-4 S-1
4. P-4 Q-2 R-1 S-3