Question

In the circuits shown below the ammeter A reads 4 amp. and the voltmeter V reads 20 volts. The value of the resistance R is

• A. Slightly more than 5 ohms
• B. Slightly less than 5 ohms
• C. Exactly 5 ohms
• D. None of the above

Answer 1

The correct option is A Slightly more than 5 ohms

According to the given circuit diagram voltage drop across the resistance is 20 volts, but the current passing through the resistance won't be 4 amp as the given voltmeter and ammeter are not ideal. Hence some current will also flow through the voltmeter.
therefore, $[R=V/i]$ will give resistance to be greater than 5 ohm as current (i) through the resistance is less than 4 amp