Question

If all meters are ideal and reading of voltmeter 3 is 6V. Power supplied by voltage source is -

• A. 10 Watt
• B. 38 Watt
• C. 20 Watt
• D. 30 Watt

Answer 1

Answer: (D)

30 Watt

Answer 2

Current through 20W = $\frac{6}{20}$

current through 10W = $\frac{6}{10}$

Total current supplied by voltage source

= $\frac{6}{10}$ + $\frac{6}{20}$

= 27 Volt

Voltage of battery = 6 + 27 = 33 volt

Power supplied = $\frac{9}{10}$× 33

= 29.7 or 30 Watt

Potential difference across 30 W =$\left( \frac{6}{10} + \frac{6}{20} \right)$× 30