Question

. When a 80V battery is connected across an unknown resistor there is a current of 100 mA in the circuit. Find the value of the resistance of the resister: *

1 point

(a) 5000 ohms

(b) 800 ohms

(c) 0.8 ohms

(d) none of these​

Answer 1

We have given the emf of the battery e=40V and the current through the circuit is I=100mA=0.1A .

The quantity we have to calculate is the resistance of the resistor, R=?.

Therefore, the value of the unknown resistor is 400Ω.

Answer 2

Given:

A circuit with a resistor and a battery

The voltage of the battery = 80V

The current flowing through the circuit = 100mA

To Find:

The value of resistance

Solution:

From Ohm's Law, we know that V ∝ I

or V = IR

Here, V = The voltage of the battery

I = The current in the circuit

R = The resistance

Also, 1mA = 10⁻³A

so 100mA = 0.1A

Substituting in the equation,

80 = 0.1 X R

or R = 80 / 0.1

= 800Ω

Hence, the value of the resistance of the resister is (b) 800 ohms.