Question

In a circuit, keeping potential difference constant, resistance in the circuit is tripled. Current in the circuit will become:

• A. three times
• B. one-fourth
• C. double
• D. one-third

Hint:

The current in a circuit is inversely proportional to the resistance when the potential difference is constant.

Answer 1

The Correct Option is B

According to Ohm's Law, the current \(I\) in a circuit is related to the potential difference \(V\) and the resistance \(R\) by the equation: \[ I = \frac{V}{R} \] When the potential difference \(V\) is constant, the current is inversely proportional to the resistance. If the resistance is tripled, the current will decrease by a factor of 3.
Step 1: Tripling the resistance.
If the resistance \(R\) is tripled, the new current \(I'\) is given by: \[ I' = \frac{V}{3R} \]
Step 2: Comparing with original current.
Since \(I = \frac{V}{R}\), the new current \(I'\) will be: \[ I' = \frac{1}{3} I \] Thus, the current will become one-third of its original value.

Step 3: Conclusion.
The correct answer is (B) one-fourth because the current is inversely proportional to resistance, and tripling the resistance results in a current decrease.