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Question : 10
Total: 26
A battery of emf 12 V 2 Ω 4 Ω
(a) Show that a voltmeter when placed across the cell and across the resistor, in turn, gives the same reading.
(b) To record the voltage and the current in the circuit, why is voltmeter placed in parallel and ammeter in series in the circuit?
(a) Show that a voltmeter when placed across the cell and across the resistor, in turn, gives the same reading.
(b) To record the voltage and the current in the circuit, why is voltmeter placed in parallel and ammeter in series in the circuit?
Solution:
(a) Relation for terminal potential
(b) Justification
(c) Explanation (parallel and series)
(a) Effective resistance of the circuitR E = 6 Ω
∴ V I =
= 2 A
Terminal potential difference across the cell,V = E
Also p.d. across4 Ω = 4 × 2 V = 8 V
Hence the voltmeter gives the same reading in the two cases.
(b) In series - current same
In parallel-potential same
(b) Justification
(c) Explanation (parallel and series)
(a) Effective resistance of the circuit
Terminal potential difference across the cell,
Also p.d. across
Hence the voltmeter gives the same reading in the two cases.
(b) In series - current same
In parallel-potential same
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