A spring when stretched by 2mm containing energy 4 J. If it is stretched by 10 mm, its potential energy becomes equal to

Options

(a) 4 J
(b) 54 J
(c) 415 J
(d) None of these

Correct Answer:

None of these

Explanation:

E₁ = 1/2 Kx₁², E₂ = 1/2 Kx₂²

E₂ / E₁ = x₂² / x₁² = (10/2)² =25

E₂ = 25 E₁

But E₁ = 4 J

E₂ = 100 J

This alternative is not given. Hence answer is ‘none’