What is the reading of ammeter in the figure. Assume that the internal resistance of battery is zero and the key is closed?
0.25 A
2.0 A
0.5 A
1.0 A
Applying Kirchhoff's laws we find : 10 = 5I1 and 10 = 5I2.
Also I = I1 + I2. Hence reading in ammeter is 2.0A.
The diagram in the figure shows a cell of e.m.f. ε=2 volt and internal resistance r = 1 ohm connected 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, and (ii) the key K is closed?