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

An iron nail sinks in the water while an iron ship floats on water. Explain the reason. 

A piece of ice floating in a glass of water melts, but the level of water in the glass does not change.

Give reasons.

Hint: Ice contracts on melting. 

Explain the following : 

Icebergs floating in sea are dangerous for ships.

For a floating body, its weight W and upthrust F_B on it are related as :

A body of weight W is floating in a liquid. Its apparent weight will be

A body floats in a liquid A of density ρ₁ with a part of it submerged inside the liquid, while in liquid B of density ρ₂ it is totally submerged inside the liquid. The densities ρ₁ and ρ₂ are related as : 

A weather forecasting plastic balloon of volume 15 m³ contains hydrogen of density 0.09 kg m^-3. The volume of equipment carried by the balloon is negligible compared to its own volume. The mass of an empty balloon alone is 7.15 kg. The balloon is floating in air of density of 1.3 kg m^-3. Calculate:

(i) The mass of hydrogen in the balloon,
(ii) The mass of hydrogen and balloon,
(iii) The total mass of hydrogen, balloon and equipment if the mass of equipment is x kg,
(iv) The mass of air displaced by balloon and
(v) The mass of equipment using the law of floatation. 

Explain the following term :

Plane mirror 

Draw diagram/diagrams to show them. 

Write three characteristics of the image formed by a plane mirror?

What is meant by lateral inversion of an image in a plane mirror? Explain it with the help of a ray diagram. 

The image formed by a plane mirror is : 

The image formed by a plane mirror is :

A man standing in front of a plane mirror finds his image at a distance 6 metre from himself. What is the distance of man from the mirror? 

An insect is sitting in front of a plane mirror at a distance 1 m from it. 
(a) Where is the image of the insect formed?

An insect is sitting in front of a plane mirror at a distance 1 m from it.
(b) What is the distance between the insect and its image?

An object is kept at 60 cm in front of a plane mirror. If the mirror is now moved 25 cm away from the object, how does the image shift from its previous position? 

An optician while testing the eyes of a patient keeps a chart of letters 3 m behind the patient and asks him to see the letters on the image of chart formed in a plane mirror kept at distance 2 m in front of him. At what distance is the chart seen by the patient? 

Two plane mirrors are placed making an angle θ in between them. Write an expression for the number of images formed of an object placed in between the mirrors. State the condition, if any.