The potential difference between the terminals of a battery in an open circuit is 2.2V. When it is connected across a resistance of 5.0 ohms, the potential falls to 1.8V. What is the current of the battery?
Correct answer: A. 0.36 A
- A. 0.36 A
- B. 2.36 A
- C. 3.39 A
- D. 4.49 A
- E. 2.71 A
Explanation
In open circuit, E = V = 2.2 V, In close circuit, V = 1.8 V, R=5ΩSo internal resistance, r=(E/V−1) R =(2.2/1.8−1) × 5 ⇒ r=10/9= 1.1ΩNow V= I(R+r)V/R+r = I2.2/ 5+1.1 = 2.2/6.1 = 0.36A
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