(English Medium) ICSE Class 10 - CISCE Question Bank Solutions for Physics

A boy lifts a load of 40 kgf through a vertical height of 2m in 5s by using a single fixed pulley when he applies an effort of 48 kgf. Calculate:
(i) the mechanical advantage, and
(ii) the efficiency of the pulley. Why is the efficiency of the pulley is not 100%?
(iii) the energy gained by the load in 5s, and
(iv) the power developed by the boy in raising the load.

What is meant by the refraction of light?

Name the phenomenon responsible in the following case:

Apparent bending of a stick in water

Name the phenomenon responsible in the following case:

Twinkling of stars

Why do the faces of persons sitting around campfire appear to shimmer?

Why does a fisherman aim at the tail of fish during spearfishing?

Why upper surface of water contained in a beaker and above eye level appears silvery?

Glass is transparent in nature. Why does glass powder look opaque? When water is poured over it, it again becomes transparent. Why?

A ray of light passes from water to air. How does the speed of light change?

Which colour of light travels fastest in any medium except air?

Why is the colour red used as a sign of danger?

Does the depth of a tank of water appear to change or remain the same when viewed normally from above?

Name one main factor on which the direction of bending of a ray of light depends.

A fish swimming in a pond seems nearer than it really is. Explain.

During sunset and sunrise, the sun is seen when it is slightly below the horizon. Give reason.

Write a relation between the angle of incidence (i), angle of emergence (e), angle of the prism (A), and angle of deviation (d) for a ray of light passing through an equilateral prism.

A glass slab is placed over a page on which the word VIBGYOR is printed with each letter in its corresponding colour.

1. Will the image of all the letters be in the same place?
2. If not, the state which letter will be raised to the maximum. Give a reason for your answer.

State the factors on which the angle of deviation depends.

Name the material for which the refractive index is found to be maximum.

What is the refractive index of vacuum