Physics 5054 · O Level · Efficiency

Efficiency — practice question

A $15\,\text{W}$ lamp is switched on for $30$ minutes. It wastes $7000\,\text{J}$ of energy. Calculate the lamp’s efficiency.

  • A$0.26$
  • B$0.35$
  • C$0.59$
  • D$0.74$

Worked solution & mark scheme

This 1-mark question has a full step-by-step worked solution and mark scheme.

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI