Physics Past Questions and Answers

A cell of internal resistance 2 ohms supplies current to a 6 ohms resistor. The efficiency of the cell is

When a resistance R is across a cell, the voltage across the terminals of the cell is reduced to two-third of its normal value. The internal resistance of the cell is

A household refrigerator is rated 200 watts. If electricity costs 5k per kWh, what is the cost of operating it in 20 days?

Which of the following ammeters may be used to measure alternating currents? i. moving-coil ammeter ii. moving-iron ammeter iii. hot-wire ammeter

The principle of operation of an induction coil is based on