Question

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

Answer 1

Answer:

75%

Explanation:

Think of the 6 ohm resistor as three 2 ohm resistors. Three 2 ohm resistors is in the load, and one 2 ohm resistor is in the source. That makes a total of four 2 ohm resistors, one of which is wasting power. 1/4 of the power is wasted in the battery, and 3/4 of the power is going to the load. The efficiency is 75%.

or

Efficiency = IR/I(R+r) x 100

= 6/(2+6) x 100

= 75%