AP EAMCET Engineering 20 Apr 2019 Shift 2 Paper

Consider the given figure,The equivalent circuit of the given circuit is shown belowThe equivalent emf is calculated as,
e‌‌=‌

‌ V1 R1 − V2 R2

1 R1 +‌ 1 R2

e‌‌=‌

‌ 5 2 − 2 1

1 2 +‌ 1 1

e‌‌=‌

1

3

V
The internal resistance is,
r=‌

R1⋅R2

R1+R2

r=‌

2×1

2+1

r=‌

2

3

Ω
The current is given as,
I=‌

e

r+R

Substitute values to find R
‌

1

5

=‌‌‌

‌ 1 3

2 3 +R

R‌‌=1Ω