logo

Very Short Question and Answers - Heating Effect of Electric Current

Q 1.
What is meant by the heating effect of electric current?

Ans:

It is the phenomenon where electrical energy passing through a conductor is partly converted into heat energy when an electric current flows.

Q 2.
Why does heat get produced when current flows through a conductor?

Ans:

Heat is produced due to collisions between moving electrons and atoms in the conductor, which causes resistance and converts some electrical energy into heat.

Q 3.
State Joule’s law of heating and give its mathematical expression.

Ans:

Joule's law of heating states that heat produced in a conductor is directly proportional to the square of the current, the resistance, and the time for which current passes. Mathematically, H = I^2Rt.

Q 4.
In the formula H = I^2Rt, what does each symbol represent?

Ans:

H = Heat produced (Joules), I = Current (Amperes), R = Resistance (Ohms), t = Time (seconds).

Q 5.
If a current of 3A flows through a 4Ω resistor for 5 seconds, how much heat is produced?

Ans:

H = I^2Rt = (3)^2 × 4 × 5 = 9 × 4 × 5 = 180 Joules.

Q 6.
Why is a coil of high resistance used in electric heaters?

Ans:

A high-resistance coil generates more heat for a given current, making it efficient for heating applications.

Q 7.
Explain how an electric bulb (incandescent) uses the heating effect of current.

Ans:

In incandescent bulbs, a thin tungsten filament is heated by current until it glows, producing light. Most of the energy, however, is emitted as heat.

Q 8.
What is the role of the heating effect in the working of an electric fuse?

Ans:

A fuse wire melts when excessive current passes through it, due to the heating effect, thus breaking the circuit and preventing damage.

Q 9.
Why are fuse wires made of materials with low melting points?

Ans:

Fuse wires are made of low melting point materials so that they melt quickly when overheated, providing safety by breaking the circuit.

Q 10.
Name two household appliances that use the heating effect of electric current for their operation.

Ans:

Electric iron and electric geyser utilize the heating effect of current.

Q 11.
What is unwanted heating? Give an example where it causes a problem.

Ans:

Unwanted heating refers to heat generated in devices or wiring where it is not useful; e.g., excessive heating in transmission wires leads to energy loss.

Q 12.
Why is high voltage and low current preferred for long-distance electric transmission?

Ans:

To minimize heat loss; since heat loss (H) is proportional to the square of the current (I^2), reducing current decreases unwanted heating.

Q 13.
List two everyday devices where the heating effect is intentionally utilized.

Ans:

Room heater and toaster.

Q 14.
Which property of the heating coil makes it suitable for use in heaters and toasters?

Ans:

High resistance and high melting point.

Q 15.
In which CBSE class 10 chapter do you study the heating effect of electric current?

Ans:

Chapter ‘Electricity’ in Science (Physics).

Q 16.
How does a geyser use the heating effect of electric current?

Ans:

The geyser has a heating element that becomes hot due to the heating effect, which then heats the water.

Q 17.
Explain why most of the energy consumed by an electric bulb is wasted.

Ans:

Because most electrical energy is converted into heat instead of light, making it inefficient.

Q 18.
Name one safety device based on the heating effect of electric current.

Ans:

Electric fuse.

Q 19.
Why should we avoid overloading electrical circuits?

Ans:

Overloading can lead to excessive heating, melting wires, damaging appliances, or causing fires.

Q 20.
How is the heating effect useful in cooking appliances like rice cookers or electric kettles?

Ans:

They contain coils that heat up when current passes, transferring this heat to cook food or boil water.

Back to Topics

Take the test