An electric heater of resistance 8 Ω draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater.
Solution and Explanation
Rate of heat produced by a device is given by the expression for power as, \(P= I^2R\)
Where,
Resistance of the electric heater, \(R= 8 \ Ω\)
Current drawn, \(I = 15 \ A\)
\(P= (15)^2 \times 8 \)
\(P= 1800 \ J/s\)
Therefore, heat is produced by the heater at the rate of \(1800 \ J/s.\)
Top Questions on Electric Power
- One kilowatt hour is equal to
- AP POLYCET - 2025
- Physics
- Electric Power
- The power of an electric motor that takes \( 5 \, A \) electric current from a \( 220 \, V \) transmission line is:
- AP POLYCET - 2025
- Physics
- Electric Power
- A bulb rated 60 W operates for 2 hours. How much energy does it consume in this time?
- VITEEE - 2025
- Physics
- Electric Power
- Electric power is the product of current and
- AP POLYCET - 2024
- Physics
- Electric Power
- A resistance R is connected across an ideal battery. The total power dissipated in the circuit is P. If another resistance R is added in series,the new total dissipated power is:
- KEAM - 2023
- Physics
- Electric Power
Questions Asked in CBSE X exam
Select TRUE statements about lymph from the following:
A. Lymph vessels carry lymph through the body and finally open into larger arteries.
B. Lymph contains some amount of plasma, proteins and blood cells.
C. Lymph contains some amount of plasma, proteins and red blood cells.
D. Lymph vessels carry lymph through the body and finally open into larger veins.
The true statements are:- CBSE Class X - 2025
- Circulatory System
- Two statements are given below. They are Assertion (A) and Reason (R). Read both the statements and choose the correct option:
Assertion (A): The French speaking community was rich in comparison to the Dutch speaking community in Belgium.
Reason (R): Dutch speaking community got the benefit of economic development and education much later.- CBSE Class X - 2025
- Power Sharing
- According to a popular quote – “Kindness is stronger than iron bars.”
Anil did not hand the thief over to the police. In what way did Anil’s act of wisdom and forgiveness transform Hari Singh?
(The Thief’s Story)- CBSE Class X - 2025
- Indian English Literature/Prose
- In a right triangle ABC, right-angled at A, if $\sin B = \dfrac{1}{4}$, then the value of $\sec B$ is
- CBSE Class X - 2025
- Trigonometry
- State two limitations of electrical impulses in multicellular organisms. Why is chemical communication better than electrical impulses as a means of communication between cells in multicellular organisms?
- CBSE Class X - 2025
- Organic Chemistry – Some Basic Principles and Techniques
Concepts Used:
Electric Power
Power is defined as the rate of doing work. Electric power is the rate at which electrical energy is transferred through an electric circuit, i.e. the rate of transfer of electricity. The symbol for Electric Power is ‘P’. SI unit of electric power is Watt.
Electric Power Formula
P = VI
From Ohm's Law, V = IR
Hence, Power can also be expressed as P = I2R