546
12 Electric Circuits
Fig. 12.18
12.34 Figure 12.19 shows a network carrying various currents. Find the current
through the ammeter A.
Fig. 12.19
12.35 A galvanometer together with an unknown resistance in series is connected
across two identical batteries, each of 1.5 V. When the batteries are connected
in series, the galvanometer records a current of 1 A and when the batteries are
in parallel the current is 0.6 A. What is the internal resistance of the battery?
[Indian Institute of Technology 1973]
12.36 In a potentiometer experiment, it is found that no current passes through the
galvanometer when the terminals of the cell are connected across 52 cm of
the potentiometer wire. If the cell is shunted by a resistance of 5 , a balance
is found when the cell is connected across 40 cm of the wire. Find the internal
resistance of the cell.
12.37 A potentiometer wire of length 100 cm has a resistance of 10 . It is connected in series with a resistance and cell of emf 2 V and of negligible internal resistance. A source of emf 10 mV is balanced against a length of 40 cm
of the potentiometer wire. What is the value of the external resistance?
[Indian Institute of Technology 1976]
12.38 A potential difference of 220 V is maintained across a 12,000 rheostat ab
(see Fig. 12.20). The voltmeter V has a resistance of 6000 and point c is at
one-fourth the distance from a to b. What is the reading in the voltmeter?
[Indian Institute of Technology 1977]
12.39 The balance point in a meter bridge experiment is obtained at 30 cm from the
left. If the right-hand gap contains resistance of 3.5 , what is the value of
the resistance in the left-hand gap?
12 Electric Circuits
Fig. 12.18
12.34 Figure 12.19 shows a network carrying various currents. Find the current
through the ammeter A.
Fig. 12.19
12.35 A galvanometer together with an unknown resistance in series is connected
across two identical batteries, each of 1.5 V. When the batteries are connected
in series, the galvanometer records a current of 1 A and when the batteries are
in parallel the current is 0.6 A. What is the internal resistance of the battery?
[Indian Institute of Technology 1973]
12.36 In a potentiometer experiment, it is found that no current passes through the
galvanometer when the terminals of the cell are connected across 52 cm of
the potentiometer wire. If the cell is shunted by a resistance of 5 , a balance
is found when the cell is connected across 40 cm of the wire. Find the internal
resistance of the cell.
12.37 A potentiometer wire of length 100 cm has a resistance of 10 . It is connected in series with a resistance and cell of emf 2 V and of negligible internal resistance. A source of emf 10 mV is balanced against a length of 40 cm
of the potentiometer wire. What is the value of the external resistance?
[Indian Institute of Technology 1976]
12.38 A potential difference of 220 V is maintained across a 12,000 rheostat ab
(see Fig. 12.20). The voltmeter V has a resistance of 6000 and point c is at
one-fourth the distance from a to b. What is the reading in the voltmeter?
[Indian Institute of Technology 1977]
12.39 The balance point in a meter bridge experiment is obtained at 30 cm from the
left. If the right-hand gap contains resistance of 3.5 , what is the value of
the resistance in the left-hand gap?