when a 12V battery is connected across an unknown resistor, there is a current of 2.5mA in the circuit. find the value os the resistance
when a 12V battery is connected across an unknown resistor, there is a current of 2.5mA in the circuit. find the value os the resistance
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Given that, a 12V battery is connected across an unknown resistor, there is a current of 2.5mA in the circuit.
We have to find the value of resistance.
From above data we have, Potential difference i.e. V = 12V and Current i.e. I = 2.5 mA.
Firstly, convert mA into A. To do this, divide the given value by 1000.
I = 2.5 mA = 2.5 × 10^-3 A
Now,
Ohm's law: The potential difference i.e. V across the ends of the wire is directly proportional to the square of current i.e. I flowing through that wire provides the temperature remains constant.
V ∝ I
V = IR (here, R is constant)
From ohm's law we can say that,
V = IR (where R is resistance)
12 = 2.5 × 10^-3 × R
12/(2.5 × 10^-3) = R
(12 × 10^3)/2.5 = R
12000/2.5 = R
4.8 × 10^3 = R
Therefore, the value of resistance is 4.8 × 10^3 ohm.