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प्रश्न
The diagram below in Fig. 8.40 shows a cell of e.m.f. ε = 2 volt and internal resistance r = 1 ohm to an external resistance R = 4 ohm. The ammeter A measures the current in the circuit and the
voltmeter V measures the terminal voltage across the cell. What will be the readings of the ammeter and voltmeter when (i) the key K is open, (ii) the key K is closed.
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उत्तर
(i) Ammeter reading = 0 because of no current
Voltage V = ϵ − Ir
V = 2 − 0 × 1 = 2 volt
(ii) Ammeter reading :
I =ε /(R + r)
I=2 / (4+1) = 2 / 5 = 0.4 amp
Voltage reading :
Voltage V = ϵ - Ir
V=2 - 0.4 x 1 = 2 - 0.4 = 1.6 V
संबंधित प्रश्न
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Define the e.m.f. (E) of a cell and the potential difference (V) of a resistor R in terms of the work done in moving a unit charge. State the relation between these two works and the work done in moving a unit charge through a cell connected across the resistor. Take the internal resistance of the cell as ‘r’. Hence obtain an expression for the current i in the circuit.
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