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Question
Identify the correct options.
(a) An ammeter should have small resistance.
(b) An ammeter should have large resistance.
(c) A voltmeter should have small resistance.
(d) A voltmeter should have large resistance.
Solution
(a) An ammeter should have small resistance.
(d) A voltmeter should have large resistance.
The ammeter is connected in series in the circuit whose current is to be measured. If the net resistance of the ammeter is high, then the amount of current that the circuit draws will have error . So, we won't be able to accurately measure the amount of current that the circuit draws from the voltage source. Thus, it should have a small resistance.
To measure the potential difference across any circuit element, the voltmeter is connected in parallel to that circuit element. If the resistance of the voltmeter is large, then maximum voltage drop occurs across the voltmeter and it will measure the correct value of the potential.
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