Question

The resistance of a resistor is reduced to half of its initial value. If other parameters of the electrical circuit remain unaltered, the amount of heat produced in the resistor will become ______.

Options

• four times

• two times

• half

• one forth

Answer 1

The resistance of a resistor is reduced to half of its initial value. If other parameters of the electrical circuit remain unaltered, the amount of heat produced in the resistor will become two times.

Explanation:

Joule’s Law of Heating:

`H = I^2Rt = V^2/R t`

If voltage V is constant, use: `H = V^2/Rt`

If current III is constant, use: H=I²Rt

`H = V^2/R t`

If R is reduced to `R/2`

`H_"new" = V^2/(R/2) t = V^2/R . 2t = 2 . H_"origional"`

2 . two times