Name and define $SI$ unit of resistance. Calculate the resistance of a resistor if the current flowing through it is $200\, mA$, when the applied potential difference is $0.8\, V$.
Name and define $SI$ unit of resistance. Calculate the resistance of a resistor if the current flowing through it is $200\, mA$, when the applied potential difference is $0.8\, V$.
$(i)$ The $SI$ unit of resistance is $Ohm (\Omega)$.
$(ii)$ If a current of one ampere flows through a wire on applying a potential difference of one volt across it, then the resistance of the wire is said to be $1 \Omega$.
$(iii)$ Here, current $( I )=200 mA =\frac{200}{1000} A =0.2 A$
Potential difference $( V )=0.8 V$
We know, $\quad V= IR$
or $\frac{0.8}{0.2}= R$
or $R=4 \Omega$
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