English Medium Class 10 - CBSE Question Bank Solutions

How does the resistance of a wire vary with its: 

 diameter? 

Why is a series arrangement not used for connecting domestic electrical appliances in a circuit?

An electric kettle rated at 220 V, 2.2 kW, works for 3 hours. Find the energy consumed and the current drawn.

Why does the connecting cord of an electric heater not glow hot while the heating element does?

Write down the formula for the heat produced when a current I is passed through a resistor R for time t.

An electric iron of resistance 20 ohms draws a current of 5 amperes. Calculate the heat produced in 30 seconds.

Explain why, tungsten is used for making the filaments of electric bulbs.

Explain why, the current that makes the heater element very hot, only slightly warms the connecting wires leading to the heater.

A heating coil has a resistance of 200 Ω. At what rate will heat be produced in it when a current of 2.5 A flows through it?

A resistance of 25 Ω is connected to a 12 V battery. Calculate the heat energy in joules generated per minute.

Derive the expression for the heat produced due to a current 'I' flowing for a time interval 't' through a resistor 'R' having a potential difference 'V' across its ends. With which name is this relation known?

 How much heat will an instrument of 12 W produce in one minute if it is connected to the heat produced by it?  

The current passing through a room heater has been halved. What will happen to the heat produced by it?

What is meant by the heating effect of current?

Name the material which is used for making the filaments of an electric bulb.

The heat produced by passing an electric current through a fixed resistor is proportional to the square of:  

(a) magnitude of resistance of the resistor
(b) temperature of the resistor
(c) magnitude of current
(d) time for which current is passed

The current passing through an electric kettle has been doubled. The heat produced will become:

(a) half
(b) double
(c) four time
(d) one-fourth 

An electric fuse works on the:
(a) chemical effect of current
(b) magnetic effect of current
(c) lighting effect of current
(d) heating effect of current

The elements of electrical heating devices are usually made of:

(a) tungsten
(b) bronze
(c) nichrome
(d) argon

The heat produced in a wire of resistance 'x' when a current 'y' flows through it in time 'z' is given by:

(a) x² × y × z
(b) x × z × y²
(c) y × z² × x
(d) y × z × x