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

A homogeneous block floats on water (a) partly immersed (b) completely immersed. In each case state the position of centre of buoyancy B with respect to the centre of gravity G of the block.

Figure shows the same block of wood floating in three different liquids A, B and C of densities ρ₁, ρ₂  and ρ₃ respectively. Which of the liquid has the highest density? Give a reason for your answer.

What is the centre of buoyancy? State its position for a floating body with respect to the centre of gravity of the body. 

A balloon filled with helium gas floats in a big closed jar which is connected to an evacuating pump. What will be your observation, if air from the jar is pumped out? Explain your answer. 

Two identical pieces, one of ice (density = 900kg per meter cube) and other wood (density = 300kg per meter cube) float on water.

1. Which of the two will have more volume submerged inside water
2. Which of two will experience more upthrust due to water.

A body is held inside water contained in a vessel by tying it with a thread to the base of the vessel. Name the three forces that keep the body in equilibrium, and state the direction in which each force acts. 

What do you mean by reflection of light? 

State which surface of a plane mirror reflects most of the light incident on it: the front smooth surface or the back silvered surface. 

Explain the following term:

Reflected ray. Draw diagram/diagrams to show them. 

Explain the following term:

Angle of incidence. Draw diagram/diagrams to show them. 

Explain the following term:

Angle of reflection. Draw diagram/diagrams to show them.

With the help of diagrams, explain the difference between the regular and irregular reflection. 

Differentiate between the reflection of light from a plane mirror and that from a plane sheet of paper.

A light ray is incident normally on a plane mirror. What is the direction of reflected ray? Show it on a diagram.

A light ray is incident normally on a plane mirror. (a) What is its angle of incidence?

Figure shows an incident ray AO and the normal ON on a plane mirror. The angle which the incident ray AO makes with mirror is 30°. (a) Find the angle of incidence. (b) Draw the reflected ray and then find the angle between the incident and reflected rays.

The diagram in Figure shows a point object P in front of a plane mirror MM₁.

(a) Complete the diagram by taking two rays from the point P to show the formation of its image.

(b) In the diagram, mark the position of eye to see the image.

(c) Is the image formed real or virtual? Explain why?

The diagram below in figure shows an object XY in front of a plane mirror MM₁ . Draw on the diagram, path of two rays from each point X and Y of the object to show the formation of its image .

A ray is incident on a plane mirror . Its reflected ray is perpandicular to the incident ray . Find the angle of incidence .