Question

when a 12v battery is connected across an unknown resistor there is a current of 2.5mA in the circuit find the value of the resistance of the resistor​

Answer 1

Given :-

• Potential difference (V) = 12 V

• Current (I) = 2.5 mA

⸕ Now,we can convert 2.5 milliamperes(mA) into ampere.

• $\rm\:current(I)=2.5\:mA$

$\rm\longrightarrow\:current\:(I)=\dfrac{2.5}{1000}\:A$

$\rm\longrightarrow\:current\:(I)=0.0025\:A$

To find :-

• Resistance (R) = ?

Solution :-

⸕ By using ohm's law,

we know that,

$\orange{\bigstar}\:\:{\underline{\boxed{\bf\pink{\dfrac{V}{I}=R}}}}$

$\rm\longrightarrow\:\dfrac{12}{0.0025}=R$

$\rm\longrightarrow\:4800=R$

$\rm\longrightarrow\:R=4800\:\Omega$

Hence,the resistance of the resistor will be 4800 Ω or 4.8 kΩ.

$\blue{\bigstar}\:\:{\underline{\boxed{\bf\purple{More\:Information}}}}$

➝ Ohm's law :- According to ohm's law at constant temperature the current flowing through a conductor is directly proportional to the potential difference across it's ends.

• The potential difference is measured by an instrument called voltmeter.