Question

The length of a given cylindrical wire is increased to double of its original length. The percentage increase in the resistance of the wire will be ______%.

Options

• 200

• 300

• 400

• 500

Answer 1

The length of a given cylindrical wire is increased to double of its original length. The percentage increase in the resistance of the wire will be 300%.

Explanation:

Resistance will increase by n₂ times if length is increased by n times.

So, R_f = 4R_i

ΔR = R_f - R_i = 3R_i

% ΔR = `(3"R"_"i")/"R"_2xx100`

= 300%