Question

When ²35U undergoes fission, 0.1% of its original mass is changed into energy. How much energy is released if 1kg of ²35U undergoes fission?

• A. 9 × 10¹0J
• B. 9 × 10¹1J
• C. 9 × 10¹2J
• D. 9 × 10¹3J

Hint:

In nuclear reactions: E = Δ m c² Even a very small loss of mass produces a huge amount of energy.

Answer 1

The Correct Option is D

Step 1: Fraction of mass converted into energy: 0.1% = 0.001 

Step 2: Mass converted: Δ m = 0.001 × 1 = 10⁻3kg 

Step 3: Using Einstein’s mass–energy relation: E = Δ m c² E = 10⁻3 × (3 × 10⁸)² E = 9 × 10¹3J