Light travels a distance of ‘10x’ units in time ‘t₁’ in vacuum and it travels a distance of ‘x’ units in time ‘t₂’ in a denser medium. Using this information answer the question that follows :

(a) ‘Light covers a distance of ‘20x’ units in time ‘t₁’ in diamond.’ State true or false.

(b) Calculate the refractive index of the medium in terms of ‘t₁’ and ‘t₂’.

A monochromatic ray of light is incident on an equilateral prism placed at minimum deviation position with an angle of incidence 45° as shown in the diagram.

(a) Copy the diagram and complete the path of the ray PQ.

(b) State two factors on which the angle of deviation depends.

Two identical marbles A and B are rolled down along Path 1 and Path 2 respectively. Path 1 is frictionless and Path 2 is rough.

(a) Which marble will surely reach the next peak?

(b) Along which path/s the mechanical energy will be conserved?

(c) Along which path/s is the law of conservation of energy obeyed?

Given are two pulleys.

(a) Copy and complete the labelled diagram connecting the two pulleys with a tackle to obtain Velocity Ratio = 2.

(b) If Load = 48 kgf and efficiency is 80% then calculate :

1. Mechanical Advantage.
2. Effort needed to lift the load