A voltmeter with resistance 500 Ω is used to measure the emf of a cell of internal resistance 4 Ω . The percentage error in the reading of the voltmeter will be

Question

A voltmeter with resistance 500 Ω is used to measure the emf of a cell of internal resistance 4 Ω . The percentage error in the reading of the voltmeter will be (A) 0.2 % (B) 0.8 % (C) 1.4 % (D) 0.4 %

Tardigrade Admin · Accepted Answer

I=(E/500+4)=(E/504) Reading of voltmeter =500 I=(500 E/504) <img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/57f598d5e25544d5277cc5ac3ebe15dc-.png" /> % error =(E-(500 E/504)/E) × 100 =(400/504) ≃ 0.8 %

Q. A voltmeter with resistance $500 Ω$ is used to measure the emf of a cell of internal resistance $4 Ω.$ The percentage error in the reading of the voltmeter will be

$0.2%$

$0.8%$

$1.4%$

$0.4%$

$I = \frac{E}{500 + 4} = \frac{E}{504}$
Reading of voltmeter $= 500 I = \frac{500 E}{504}$

$%$ error $= \frac{E - \frac{500 E}{504}}{E} \times 100$
$= \frac{400}{504} ≃ 0.8%$

Q. A voltmeter with resistance 500Ω is used to measure the emf of a cell of internal resistance 4Ω. The percentage error in the reading of the voltmeter will be

0.2%

0.8%

1.4%

0.4%