Question

when a 4V battery is connected across an unknown resistor there is a current of 100mA in the circuit . The value of the resisitance of the resist is : a] 4ohm. b. 40 ohm. c.400ohm. d. 0.4 ohm ​

Answer 1

Given:-

Voltage of battery = 4 V

Current in unknown resistance = 100 mA

=> 10-¹ A

Find:-

The value of the resistance (R).

Solution:-

Aaccording to Ohm's Law :

The current flowing through the conductor is directly proportional to the Voltage or potential difference across the ends of the terminals at constant temperature and pressure.

So,

$\sf{V \:= I \:\times\: R }$

Here, R is constant

Substitute the known values in above formula

=> $\sf{4\:=\:10^{-1}\:\times\:R}$

=> $\sf{\dfrac{4}{10^{-1}}\:=\:R}$

=> $\sf{4\:\times\:10\:=\:R}$

=> $\sf{40\:=\:R}$

=> $\sf{R\:=\:40\:ohm}$

•°• The resistance of the resist is 40 ohm.

Answer :-

Option b) 40 ohm

Answer 2

Answer:-

$\bold{ \: R = 40}$ohm

Explanation:-

Given:-

• V(Potential Diff.) = 4V

I(Current) = 100 mA = $100 \times 10^-3 A$

To Find:-

Resistance (R)

Solution:-

$\blue{\boxed{\bold{\pink{V = IR}}}}$

${\rightarrow} \: R = \dfrac{V}{I}$

${\rightarrow} \: R = \dfrac{4}{100 \times 10^-3}$

${\rightarrow} \: R = \dfrac{4}{10^-1}$

${\rightarrow} \: R = 40$ohm

$\green{\boxed{\bold{\red{R = 40 \: ohm }}}}$