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

'The centre of gravity of a freely suspended body always lies vertically below the point of suspension'.

A uniform flat circular rim is balanced on a sharp vertical nail by supporting it at point A, as shown in the figure. Mark the position of the centre of gravity of the rim in the diagram by the letter G.

The figure shows three pieces of cardboard of uniform thickness cut into three different shapes. On each diagram draw two lines to indicate the position of the centre of gravity G.

The centre of gravity of a uniform ball is ______.

1. Name the particles which are responsible for the flow of current in a metallic wire.
2. Explain the flow of current in a metallic wire on the basis of movement of the particles named by you above in part (a).
3. What is the cause of resistance offered by the metallic wire in the flow of current through it?

Two wires, one of copper and other of iron, are of the same length and same radius. Which will have more resistance? Give reason. 

What is the velocity ratio of a single movable pulley? How does the friction in the pulley bearing affect it?

In a single movable pulley, if the effort moves by a distance x upwards, by what height is the load raised?

Draw a labelled diagram of an arrangement of two pulleys, one fixed and other movable. In the diagram, mark the directions of all forces acting on it. What is the ideal mechanical advantage of the system? How can it be achieved?

Give reason for the following:

The efficiency of a movable pulley is always less than 100%.

What do you mean by the term local earthing? Explain how it is done.

The metal case of an electric appliance is earthed explain the reason.

1. The earthing of an electric appliance is useful only if the fuse is in the live wire. Give the reason.
2. Name the part of the appliance which is earthed.

For earthing an electrical appliance, one has to remove the paint from the metallic body of the appliance where the electrical contact is made. Explain the reason.

Why is it necessary to have an earth wire installed in a power circuit, but not in a lighting circuit?

A movable pulley is used as ______.

Name the material used for making the connection wires. Give a reason for your answer.

Name a material which is used for making the standard resistor. Give a reason for your answer.

Name the material used for making a fuse wire. Give a reason.

Name the material used for filament of an electric bulb.