Question

A cell when connected to an external resistance of 2 ohm shows a potential difference of 1.2 V if another resistance of 2 ohm is connected in parallel potential difference drops to 1.0 V find the EMF and internal resistance of cell

Answer 1

Answer:

Final Answer : 1.95V

Underst\nding :

1) Potential Difference across terminal of a cell,

V = E - I r

where

E = EMF of cell =2V

r = internal resistance =0.1ohm

i = current in circuit.

R = External Resistor

Steps :

1) Cell and External resistor are connected directly,

=> R(eq) = r + R

=0.1 + 3.9 = 4.0 oh m

2) Current in circuit,

I = E / R(eq)

= 2/4.0 = 1/2 =0.5 A

3) Potential Difference across terminal of a cell,

V = E - Ir

= 2 - 0.5 *0.1

= 1.95 V.

hope this will help u:)