Question

In the circuit shown, the galvanometer $ G $ of resistance $ 60 \, \Omega $ is shunted by a resistance $ r = 0.02\, \Omega $ . The current through $ R $ is nearly $ 1\,A $ . The value of resistance $ R $ is (in ohm) is nearly

• A. $ 1.00\, \Omega $
• B. $ 5.00\, \Omega $
• C. $ 11.00\, \Omega $
• D. $ 60.00\, \Omega $

Answer 1

Answer: (B)

Equivalent resistance of the combination
$ = \frac{GS}{G+S} = \frac{60 \times 0.02}{60+ 0.02}$
$ = 0.0199$
Total resistance $= R + 0.0199$
$V = iR'$
$5 = 1 \times R + 0.0199$
$R = 5- 0.0199 = 4.98 \approx 5.00 \,\Omega$