Question

What is the equivalent resistance of a voltmeter with coil resistance $R_c=1k\Omega$ and series resistance of 100 k$\Omega$?

• A. $101k\Omega$
• B. $\frac{100}{101}k\Omega$
• C. $\frac{101}{100}k\Omega$
• D. $99k\Omega$

Answer 1

The correct option is A $101k\Omega$

Series resistor is connected in series with the coil to ensure very small current through the combination.
$R_{eq}=R_c+R_s{R}_{eq}=(100+1)k\Omega =101k\Omega$