A student traces the path of a ray of light through a glass prism for different angles of incidence. He analyses each diagram and draws the following conclusion:

I. On entering the prism, the light ray bends towards its base.

II. Light ray suffers refraction at the point of incidence and at the point of emergence while passing through the prism.

III. An emergent ray bends at a certain angle to the direction of the incident ray.

IV. While emerging from the prism at the second surface, the angle of refraction is less than the angle of incidence at that surface.

Which of the above inferences are correct?

1. I, II and III
2. I, III and IV
3. II, III and IV
4. All of these.

A metal ball is whirled inside a ring placed on a table, as shown in the diagram P. The diagram Q shows the motion of the ball after the ring is lifted.

Which of the following diagrams shows the correct position of the metal ball in the ring when the ring is lifted?

Assertion (A) : When the displacement is zero, then the work is zero. So, if the work done is zero, then it necessarily means the displacement is zero.

Reason(R) : Work done is calculated by the relation 𝑊=𝐹𝑆 𝑐𝑜𝑠 𝜃

1. A and R are true, and R is the reason for A.
2. A and R are true, and R is not the reason for A.
3. A is true, but R is false.
4. A is false, but R is true.

Which of the following statement is CORRECT?

The frequency of a stretched string is:

1. directly proportional to its length but inversely proportional to the tension of the wire.
2. inversely proportional to its length but directly proportional to the tension of the wire.
3. directly proportional to the square root of its length but inversely proportional to the tension of the wire.
4. inversely proportional to its length but directly proportional to the square root of the tension of the wire.