Question

From the circuit-diagram given below choose the correct options:-

• A. If a cell of emf 1V is connected between points A & B and R = 3 ohm then 4 J of heat is developed in equivalent resistor in two seconds
• B. The current flowing through the equivalent resistor is 20A when a cell of emf 20 V is connected between A & B
• C. If point A & B is connected to a cell, the potential difference across all the three resistors would be different.
• D. If point A & B is connected to a cell, the power developed in all the three resistors would be different

Answer 1

The correct option is B

The current flowing through the equivalent resistor is 20A when a cell of emf 20 V is connected between A & B

This circuit simplifies in to 3 resistors connect parallely to a cell. Now, since they are in parallel the equivalent resistance becomes and R = 3 ohm so, the equivalent resistance becomes 1 ohm, and if it is connected to 1 V battery then the current would also be one ampere and so the heat developed would be (1)²(1)(2) = 2 J. Now, when emf of the cell is 20 V then the current = V/R = 20/1 = 20 A. Since the three resistors simplifies to a parallel connection therefore the potential difference across every resistor would be same. The power developed in all the three resistors would be same as power = (V)²/R. 'V' would be same in every resistor and 'R' is equal, So would be the power.