Moving Charges and Magnetism - Result Question 74
76. A circuit contains an ammeter, a battery of $30 V$ and a resistance $40.8 \Omega$ all connected in series. If the ammeter has a coil of resistance $480 \Omega$ and a shunt of $20 \Omega$, the reading in the ammeter will be:
[2015 RS]
(a) $0.25 A$
(b) $2 A$
(c) $1 A$
(d) $0.5 A$
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Answer:
Correct Answer: 76. (d)
Solution:
- (d) From circuit diagram
Resistance of ammeter $=\frac{480 \times 20}{480+20}=19.2 \Omega$.
Total resistance $R=40.8+19.2=60 \Omega$
Reading in the ammeter $i=\frac{V}{R}$
$ =\frac{30}{40.8+19.2}=0.5 A $
