Question

12 The potential difference between the points A and B of the electrical circuit,
below is

0.03A
25ohm
20 ohm
30 ohm

A. 1.5V
B. 1.0V
C. 0.75 V
D. 0.5V
E. 1.25 V

Answer 1

Answer:

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.

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