Image Formation by Lenses

Q.

1. 71 cm²

2. 61.55 cm²

3. 6.125 cm²

4. 61.25 cm²

Q.

Himanshu has two lenses A and B. When he touches both the lenses he finds that A is thicker at the centre than the edges and B is thinner at the centre as compared to its edges. He has to focus sunlight on a particular point. Which of the following statement is true?

1. He should use lens B

2. He should use lens A

3. Neither of the lenses can be used

4. Insufficient information

Q.

To see the virtual image of an object formed in the lens, the object and the observer should be:

1. on the different sides of the lens

2. can’t be said

3. position of the observer does not matter

4. on the same side of the lens

Q.

Convex lens are the lens which are thicker in the middle and thinner at the edges.

1. True

2. False

Q.

A concave lens always forms a virtual image.

1. True

2. False

Q.

A concave lens is also known as a converging lens.

1. True

2. False

Q.

A convex lens always forms a virtual image.

1. True

2. False

Q.

Himanshu was challenged by his friend Sushweta to differentiate between a plane, concave and convex mirror without touching them. He placed a candle in front of each of the mirrors and observed that they showed different behaviour. The mirror I always formed a diminished image, mirror II always formed an image of same height while for mirror III the image was enlarged when the candle was placed close to the mirror. Can you help him to identify them?

1. I – Plane mirror, II – Concave mirror, III – Convex mirror

2. I – Concave mirror, II – Plane mirror, III – Convex mirror

3. I – Convex mirror, II – Plane mirror, III – Concave mirror

4. I - Plane Mirror, II - Convex mirror, III - Concave mirror

Q.

Akash placed a candle in front of a convex lens and obtained an image as shown below.

Now he covered the upper half of the lens with a black paper. What can you say about the image formed?

1. No difference will be observed even after covering the upper half of lens with black paper

2. Image of same size will be formed but its intensity will be less

3. Image of only the lower half of the candle will be formed

4. No image will be formed

Q.

Which of the following figure represents a convex lens?

1. 

2. 

3. 

4. None of these