NEET2026PhysicsChapterActual
An electric kettle is rated at 1.2 kW for a 240 V supply. If the line voltage drops to 180 V due to heavy load, what will be the actual power consumed by the kettle? (Assume the resistance of the heating element remains constant)
Options
- A900 W
- B675 W
- C1600 W
- D2133 W
Correct answer
B. 675 W
Step-by-step solution
The resistance of the heating element is given by R = V₁^2 P₁ . Since the resistance remains constant, the new power consumed is P₂ = V₂^2 R . Taking the ratio of the powers, we get P₂ = P₁ ( V₂ V₁ )^2 . Substituting the given values P₁ = 1200 W, V₁ = 240 V, and V₂ = 180 V: P₂ = 1200 ( 180 240 )^2 P₂ = 1200 ( 3 4 )^2 P₂ = 1200 9 16 = 675 W. Answer: 675 W