The emf of the cell in the following circuit is 9V. The reading on the high resistance voltmeter is 7.5V what is the current l?
Correct answer: D. 0.5A
- A. 0.1A
- B. 0.6A
- C. 2A
- D. 0.5A
Explanation
The high-resistance voltmeter, which is connected across the 9.0V battery, reads a p.d. of 7.5V. This means that there is some lost volts in the battery and this is due to its internal resistance.Lost volts in battery = 9.0 - 7.5 = 1.5VFrom Kirchhoff's law, the sum of p.d. in the circuit is equal to the e.m.f. in the circuit.p.d. across the 152 resistor = 7.5VOhm's law: V = IRCurrent I through the 1552 resistor = V / R = 7.5 / 15 = 0.5A
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Steady current relates charge flow to potential difference, resistance and resistivity, including how temperature changes a conductor's resistance. Sources with internal resistance have terminal voltage below their emf when delivering current, and maximum power output occurs under a specific load condition rather than at zero resistance.
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