Question

Six cells each having emf 1.4 volt and internal resistance 1/6 ohm are connected in series by a student. It is found that two cells were wrongly connected with its internal terminal reversed. When the series combintion is connected to an exteral resistance of 1.8 ohm the current flowing through the circuit is -

Answer 1

Explanation:

ANSWER

The total emf of the 20 cells connected in series are 1.8×20=36V.

Hence, the total voltage in the circuit is 220V−36V=184V.

From the Ohm's law, V=IR. Substituting the values of Voltage and current in the equation

R=

I

V

,wegetR=

15

184

=12.27ohms.

The internal resistance of the 20 cells is given as 20×0.1ohms=2ohms.

So, the total resistance R in the circuit is =12.27−2ohms=10.27ohms.

Hence, the resistance in the circuit is 10.27 ohms