Question 357: Current Electricity

Question

For the circuit shown, with R
1
= 1.0W, R
2
= 2.0 W,
E
1
= 2 V and E
2
= E
3
= 4 V, the potential
difference between the points 'a' and 'b' is
approximately  (in V):
![](https://imagex.cdn.examgoal.net/MJPvbpEw9y3IGasbM/dIS19QGrMJ479pKRzs1SdVc5ovaeu/QNTziT1XyJqDnShuqj6AeZ/image.png)

Accepted Answer

Given circuit is
Above circuit can be viewed as
This is a parallel combination of three cells or in other words, a parallel grouping of three cells with internal resistances.
So, ${V_{ab}} = {E_{eq}} = {{{I_{eq}}} \over {{r_{eq}}}} = {{{{{E_1}} \over {{r_1}}} + {{{E_2}} \over {{r_2}}} + {{{E_3}} \over {{r_3}}}} \over {{1 \over {{r_1}}} + {1 \over {{r_2}}} + {1 \over {{r_3}}}}}$
$ = {{{2 \over 2} + {4 \over 2} + {4 \over 2}} \over {{1 \over 2} + {1 \over 2} + {1 \over 2}}} = {{10} \over 3}V \approx 3.3\,V$
![](['https://app-content.cdn.examgoal.net/fly/@width/image/1l36sex8z/4b5a125d-7390-4c4e-b5aa-a2d60a946cbb/169ea230-d406-11ec-b808-5752a3163b13/file-1l36sex90.png?format=png', 'https://app-content.cdn.examgoal.net/fly/@width/image/1l36sfe2x/dd52f608-7845-4d47-b105-48bed6449a14/239f2f90-d406-11ec-b808-5752a3163b13/file-1l36sfe2y.png?format=png'])

Answer

3.3

Answer

2.7

Answer

2.3

Answer

3.7

Current Electricity

For the circuit shown, with R 1 = 1.0W, R 2 = 2.0 W, E 1 = 2 V and E 2 = E 3 = 4 V, the potential difference between the points 'a' and 'b' is approximately (in V):

Choose the correct answer: