Question

A piece of fuse wire melts when a current of 15 ampere flows through it. With this current, if it dissipates 22.5 W, the resistance of fuse wire will be
1. zero
2. 10 Ω
3. 1 Ω
4. 0.10 Ω

Answer 1

Correct Answer - Option 4 : 0.10 Ω

CONCEPT : 

• Electrical power is defined as the product of Voltage and current in the electrical circuit and is given by

\(⇒ P = V I = I^2R= \frac{V^{2}}{R}\)

Where I = Current, R = Resistance, V = Voltage 

CALCULATION :

Given - P = 22.5 W, i = 15 A

• The amount of power dissipated is given by

⇒ P = i²R

\(⇒ R = \frac{p}{i^{2}}\)

Substituting the given values

\(⇒ R = \frac{22.5}{15^{2}} = 0.10\Omega \)

• Hence, option 4 is the answer.