Question

When a 20V battery is connected across an unknown resistor there is a current of 10 mA in the circuit. Find the value of the resistance of the resistor: *​

Answer 1

• Voltage=V=20V
• Current=10mA=I
• Resistance=R=?

Using ohms law

$\boxed{\sf \dfrac{V}{I}=R}$

$\\ \sf\longmapsto Resistance=\dfrac{20}{10}$

$\\ \sf\longmapsto Resistance=2\Omega$

Answer 2

Answer:

$\sf \: Resistance \: \: of \: unknown \: resistor \:is \: \\ \sf \: R = 2 \: k\Omega \: \: \: or \: \: \: 2000 \: \Omega \:$

Explanation:

Given,

★ Battery voltage V = 20 V

★ Current I = 10 mA = 0.01 A [ Cause, 1A = 100 mA]

To find :

★ Resistance (R) of unknown resistor.

Solution :

we know that,

$\: \: \: \: \: \: \: \: \: \: \: V = IR \\ \implies \: R = \frac{V }{ I} \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = \frac{20}{0 .01} \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 2000\Omega \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 2 \: k\Omega$