Question

In the diagram shown, the reading of voltmeter is 20 V and that of ammeter is 4 A. The value of R should be (Consider given ammeter and voltmeter are not ideal)

• A. Equal to $5\Omega$
• B. Greater from $5\Omega$
• C. Less than $5\Omega$
• D. Greater or less than $5\Omega$ depends on the material of R

Answer 1

Answer: (C)

Less than $5\Omega$

Answer 2

If resistance of ammeter is r then

$20 = (R + r)4$ ⇒ $R + r = 5$ ⇒ $R < 5\Omega$