(English Medium) ICSE Class 9 - CISCE Question Bank Solutions

Calculate the number of images formed in two plane mirrors, when they are held at the angle of (i) 72° (ii) 36°.

Draw a neat two ray diagram for the formation of images in two plane mirrors, when mirrors are at right angles to each other.

Draw a neat two ray diagram for the formation of images in two plane mirrors, when mirrors are at facing each other.

What should be the minimum size of a plane mirror, so that a person 182 cm high can see himself completely?

A boy stands 4 m away from the plane mirror. If the boy moves `1/2` m towards the mirror, what is now the distance between the boy and his image? Give a reason for your answer. 

What must be the minimum length of a plane mirror in which a person can see himself full length? Draw a diagram to justify your answer. Does the distance of a person from the mirror affect the above answer?

An insect is sitting in front of a plane mirror at a distance of one meter from it.

1. Where is the image of insect formed?
2. What is the distance between insect and its image?
3. State any two characteristics of image formed in a plane mirror.

Parallel rays are incident:

1. on regular surface and
2. on irregular surface. In what respect do reflected rays in (1) differ from those of (2)?

Write down the letters of the word ‘POLEX’ as seen in a plane mirror, held parallel to the plane of this paper.

Select the correct option:

A ray of light is incident on a concave mirror. If it is parallel to principal axis, the reflected ray will:

Select the correct option:

In case of concave mirror, the minimum distance between an object and its real image is:

Select the correct option:

If an incident ray passes through the centre of curvature of a spherical mirror, the reflected ray will:

State briefly, how and why the atmospheric pressure of a place varies with the altitude. Draw an approximate graph to illustrate this variation.

State two advantages of an aneroid barometer.

Explain, why steel is used in preference to soft iron for making permanent magnets while soft iron is used in preference to steel for making electromagnets.

A hollow metal cylinder of length 10 cm floats in alcohol of density 0.80 g cm^-3, with 1 cm of its length above it. What length of cylinder will be above copper sulphate solution of density 1.25 g cm^-3?

What fraction of metal of density 3400 kgm^-3 will be above the surface of mercury of density 13600 kgm^-3, while floating in mercury?

A test tube weighing 17 gf, floats in alcohol to the level P. When the test tube is made to float in water to the level P, 3 gf of the lead shots are added in it. find the R.D. of alcohol.

A test tube loaded with lead shots, weighs 150 gf and floats upto the mark X in water. The test tube is then made to float in alcohol. It is found that 27 gf of lead shots have to be removed, so as to float it to level X. Find R.D. of alcohol.

Why does a ship make of iron not sink in water, while an iron nail sinks in it?