Question

A 10V battery with internal resistance 1Ω and a 15V battery with internal resistance 0.6Ω are connected in parallel to a voltmeter (see figure). The reading in the voltmeter will be close to: 

• A. 12.5 V
• B. 24.5 V
• C. 13 V
• D. 11.9 V

Hint:

Parallel batteries share a weighted average voltage based on internal resistance.

Answer 1

The Correct Option is D

Step 1: Equivalent voltage for parallel sources: V = ((E₁)/(r₁)+(E₂)/(r₂))/((1)/(r₁)+(1)/(r₂))
Step 2: Substitute values: V=((10)/(1)+(15)/(0.6))/((1)/(1)+(1)/(0.6)) =(10+25)/(1+1.67) ≈ 11.9V