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

An illuminated object lies at a distance 1.0 m from a screen. A convex lens is used to form the image of the object on a screen placed at a distance of 75 cm from the lens. Find:

1. the focal length of the lens, and
2. the magnification.

An object is placed at a distance of 20 cm in front of a concave lens of focal length 20 cm. find: the magnification of image.

The magnification by a lens is -3. Name the lens and state how are u and v related?

The magnification by a lens is +0.5. Name the lens and state how are u and v related?

The maximum magnifying power of a convex lens of focal length 5 cm can be ______.

Three resistors of 6.0 Ω, 2.0 Ω and 4.0 Ω are joined to an ammeter A and a cell of emf 6.0 V as shown in the following figure. Calculate :

1. the effective resistance of the circuit.
2. the reading of ammeter.

What do you mean by power rating of an electrical appliance? How do you use it to calculate 

(a) the resistance of the appliance and

(b) the safe limit of the current in it, while in use?

Why do we usually use isotopes emitting gamma radiations as radioactive tracers in medical science?

Name two main sources of nuclear radiations. How are these radiations harmful?

A given metallic wire of resistance R is doubled on itself. What will be its new resistance?

How does the resistance of an alloy, vary with temperature?

Bends in a rubber pipe reduce the flow of water through it. How would the bands in a wire affect its electric resistance?

Name the material of wire used for making standard resistances. Give a reason.

What material is used for making wire to prepare heating coils? Give a reason.

Why are thick copper wires used as connecting wires?

State the effect of rise in temperature on the resistance of semi-conductors.

Write an expression for the resistance of a conducting wire in terms of its length and area of cross-section.

How does the resistivity of a semiconductor depend on temperature?

How does the resistivity of an alloy such as constantace depends on temperature.

Define the term resistivity and state its S.I. unit. Which will have higher resistivity a conductor or an insulator.