English Medium Class 10 - CBSE Question Bank Solutions

An electric heater is connected to the 230 V mains supply. A current of 8 A flows through the heater. 

(b) How much energy is transferred to the heater each second?

An electric room heater draws a current of 2.4 A from the 120 V supply line. What current will this room heater draw when connected to 240 V supply line?

What is nichrome? State its one use.

Give two reasons why nichrome alloy is used for making the heating elements of electrical appliances.

Why are the coils of electric irons and electric toasters made of an alloy rather than a pure metal?

How does the resistance of a wire vary with its: 

 diameter? 

Which organ acts as a pump in the circulatory system?

What is the liquid part of the blood called? What is the function of platelets in the blood?

With which human organ system (or human systems) is vena cava associated?

State the functions of blood in our body.

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

What is meant by human circulatory system? Name the organs of the circulatory system in humans.

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

The cells in our blood which destroy disease-causing germs are:

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?