PHYSICS 10 SCIENCE · 2026–27 · Textbook worked examples · p. 177

Textbook mass–energy illustration

A mass defect of 1 × 10⁻⁴ kg is converted to released energy. Find energy using c = 3 × 10⁸ m s⁻¹.

1 × 10⁻⁴ kg کمیتی کمی توانائی بنتی ہے۔ c = 3 × 10⁸ m s⁻¹ سے توانائی نکالیں۔

Solution & explanation

  1. Mass defect is already in kilograms.

  2. Use E = Δmc².

    E=Δm×c2

  3. Substitute.

    E=(3×108)210000

  4. Square the speed.

    c2=9×1016

  5. Multiply powers: 10⁻⁴ × 10¹⁶ = 10¹².

    E=9×1012

  6. State the result in joules.

E = 9 × 10¹² J

Independent study material · English-medium textbook p. 177 · Original book ↗