NCERT Class VII Science Solutions: Chapter 15 – Light Part 2

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VERY SHORT ANSWER QUESTIONS

Question 9:

The image formed by a lens is always virtual, erect and smaller in size for an object kept at different positions in front of it. Identify the nature of the lens.

Answer:

Concave lens.

Question 10:

Fill in the blanks:

  1. The inner surface of a steel spoon acts as a ________ mirror.

  2. The outer surface of a flat steel plate acts as a _________ mirror.

  3. The outer shining surface of a round bottom steel bowl acts as a __________ mirror.

  4. The inner surface of the reflector of a torch acts as a _________ mirror.

Answer:

  1. The inner surface of a steel spoon acts as a concave mirror.

  2. The outer surface of a flat steel plate acts as a plane mirror.

  3. The outer shining surface of a round bottom steel bowl acts as a convex mirror.

  4. The inner surface of the reflector of a torch acts as a concave mirror.

Question 11:

State whether the following statements are true or false.

  1. A concave lens can be used to produce an enlarged and erect image.

  2. A convex lens always produces a real image.

  3. The sides of an object and its image formed by a concave mirror are always interchanged.

  4. An object can be seen only if it emits light.

Answer:

  1. A concave lens can be used to produce an enlarged and erect image. (False)

  2. A convex lens always produces a real image. (False)

  3. The sides of an object and its image formed by a concave mirror are always interchanged. (True)

  4. An object can be seen only if it emits light. (False)

SHORT ANSWER QUESTIONS

Question 12:

What type of mirror is used as a side mirror in a scooter? Why is this type of mirror chosen?

Answer:

Convex mirror. Convex mirrors can form images of objects spread over a large area. So these help the drivers to see the traffic of a large area behind them.

Image of convex mirror

Convex Mirror

Image of convex mirror

Question 13:

Observe the figures given as Figure carefully.

As showing in images is a observe the figures given as Figure carefully

Observe the Figures Given as Figure Carefully

As showing in images is a observe the figures given as Figure carefully

The given figures show the path of light through lenses of two different types, represented by rectangular boxes A and B. What is the nature of lenses A and B?

Answer:

  1. Convex lens.

  2. Concave lens.

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