Question

Certain amount of current is passing through a resistor. If 12 ohm resistance is connected in series with it, the current becomes one third. Find the resistance of the resistor​.​

Answer 1

Answer: 6 ohms

Explanation:

We know that V=IR [Ohm’s law]

and as it is a series connection, V will remain constant, and we are using same amount of current,

so our first equation is V=IR₁

and second is V=I/3(R₁+12) =IR₁+I x 12/3

putting the two eq together,

IR₁ = IR₁+I x 12/3

3IR₁ = IR₁+I x 12

3IR₁ - IR₁ = I x 12

2IR₁ = I x 12

IR₁/I = 12/2

R₁ = 6 ohms