Question

Heat generated in a resistive wire is:
1. proportional to the square of the time of current flow
2. proportional to the square of the current flowing in the wire
3. proportional to the square of the resistance of the wire
4. proportional to the cube of the resistance of the wire

Answer 1

Correct Answer - Option 2 : proportional to the square of the current flowing in the wire

The correct answer is proportional to the square of the current flowing in the wire.

• The heat generated in a resistive wire is equal to the power dissipated through it. 
• The power dissipated through a resistance is equal to V x I or P = I2 R or P = V2/R, where, V =  voltage across the resistor, I = current flowing through the resistor, R = resistance of the resistor.
• Hence, from the formula, it is clear that the heat generated or power dissipated is proportional to the square of the current flowing in the wire. 

• Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points. 
• Ohm’s law may be expressed mathematically as V/I = R, where, V =  voltage across the resistor, I = current flowing through the resistor, R = resistance of the resistor.