List of top Physics Questions on Power in Electric Circuits

In the circuit given below, identify the lamp (L1, L2, L3 or L4) whose failure would not interrupt the power supply to the other lamps.

The correct formula to calculate the equivalent resistance of R\(_1\) and R\(_2\) when connected in parallel, is:

An electric iron rated 1100 W, 220 V is operated for 5 hours.
Calculate:
(a) the minimum rating of the fuse required.
(b) the energy consumed in kWh.
(c) the cost of the energy consumed, if the rate is Rupees 10 per unit.

In the combinations of resistors shown below, calculate:
(a) the resistance across AB when the switch S is open.
(b) the resistance across AB when the switch S is closed.

Bulb A rated 160 W, 40 V and Bulb B rated 40 W, 40 V are connected as shown in the diagram.
(a) Calculate the ratio V\(_1\) : V\(_2\)
(b) If the bulb A fuses, the current in the circuit remains the same. State True or False.

A resistance R is connected across a cell with a switch and a rheostat in series. A voltmeter is connected parallel across the cell. Current in the circuit is increased using the rheostat.
(a) How will the voltmeter reading change? (increase / decrease / remain the same)
(b) Justify your answer stated in (a) above.

Two batteries of emfs 3V and 6V and internal resistances 0.2 and 0.4 are connected in parallel. This combination is connected to a 4 resistor. Find:
(i) the equivalent emf of the combination
(ii) the equivalent internal resistance of the combination
(iii) the current drawn from the combination