Problem 162 - A Complete Resource Book in Physics for JEE Main

Question

An energy source will supply a constant current into the load, if its internal resistance is (A) Equal to the resistance of the load. (B) Very large as compared to the load resistance. (C) Zero. (D) Non-zero but less than the resistance of the load.

Step-by-Step Solution

Answer

The correct answer is (C). The energy source will supply a constant current into the load if its internal resistance is zero.

Step 1: Understand Circuit Parameters and Ohm's Law

First, the terms need to be understood. The internal resistance of an energy source or a battery relates to the opposition it offers to the current. Ohm's Law, \(V = IR\), where \(V\) is voltage, \(I\) is current, and \(R\) is resistance, informs the relations among these parameters. The total resistance of a circuit is the sum of internal and load resistances.

Step 2: Understand the Effects of Different Internal Resistances

Now, for different choices about the internal resistance, the effect on the current delivered to the load should be examined:(A) When the internal resistance is equal to the load resistance, the potential drop is equally spread over each resistor, and the current is not constant. (B) If the internal resistance is very large as compared to the load resistance, less current will reach the load due to the significant potential drop across the internal resistance.(C) If the internal resistance is zero, the whole of the source voltage would appear across the load, causing a constant current through the load. (D) If it’s non-zero but less than the resistance of the load, some of the potential drop would occur across the internal resistance causing fluctuations in the current reaching the load.

Step 3: Identify the Correct Option

From the above analysis, the condition for the energy source to supply a constant current into the load is when its internal resistance is zero. Therefore, the correct answer is choice (C).