An ammeter has a resistance of 0.1 Ω. It can read upto 5 A. To convert this into voltmeter to read 100 V, the resistance to be used is

Question

An ammeter has a resistance of 0.1 Ω. It can read upto 5 A. To convert this into voltmeter to read 100 V, the resistance to be used is (A) 19.9 Ω in series (B) 19.9 Ω in parallel (C) 199 Ω in series (D) 0.19 Ω in parallel

Tardigrade Admin · Accepted Answer

Here, V= I (RA+ R) or, 100 = 5 (0.1 + R) or, R = (20- 0.1) ⇒ R = 19.9 Ω

Q. An ammeter has a resistance of $0.1Ω$ . It can read upto $5 A$ . To convert this into voltmeter to read $100 V$ , the resistance to be used is

$19.9Ω$ in series

$19.9Ω$ in parallel

$199Ω$ in series

$0.19Ω$ in parallel

Here,
$V = I (R_{A} + R)$
or, $100 = 5 (0.1 + R)$
or, $R = (20 - 0.1)$
$\Rightarrow R = 19.9 Ω$

Q. An ammeter has a resistance of 0.1Ω. It can read upto 5A. To convert this into voltmeter to read 100V, the resistance to be used is

19.9Ω in series

19.9Ω in parallel

199Ω in series

0.19Ω in parallel