Boojho planned an activity to observe an object A through pipes as shown in figure so that he could see objects which he could not directly see.

(a) Mention how many mirrors should he use to see the objects.
(b) Indicate the positions of the mirrors in the figure.
(c) State what must be the angle w.r.t. the incident light at which he should place the mirrors.
(d) Indicate the direction of rays in the figure.
(e) If any of the mirrors is removed, will he be able to see the objects?

5

(a)

Explain the process which enables us to perceive motion in a cartoon film.

5

(a)

There is a mistake in each of the following ray diagrams given as figure (a), (b), and (c). Make the necessary correction(s).

5

(a)

Two students of your class brought three big plane mirrors in their classroom for science fair. They fixed the three mirrors. One at the ceiling and the other two on the adjacent walls of the room. Since every student was able to see six images of himself/herself. Students of other classes also come to see this and felt happy. A student of class VII was determined to know the reason behind it. He went to the library, consult other students and next day come up with the correct answer.
(a) Mention the value were depicted by the students of class VII?
(b) Also, give the reason for seeing six images.

5

(a)

How is the phenomenon of reflection used in making a kaleidoscope? What are the applications of a kaleidoscope?

5

(a)

Explain the reason for the following statement. We usually take some time to see the objects in a dim light room, when we enter into the room from bright sunlight outside.

5

(a)

Describe an activity to show that the incident ray, the reflected ray and the normal at the point of incidence, all lie in the same plane.

5

(a)

Describe the construction of a kaleidoscope.

5

(a)

Write down the names of parts of the eye in the blank spaces shown in fig. below.

5

(a)

How can you take care of the eyes?

5

(a)