Efficiency and energy resources

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Question 34
Easy

An LED lamp transfers energy from an electrical supply as shown in the energy diagram below.

An energy flow diagram for an LED lamp. The input arrow on the left is labelled 'Total electrical energy supplied = 15,000 J'. This splits into two output arrows: a straight arrow pointing to the right is labelled 'Useful light energy = 6,000 J', and a downward arrow is labelled 'Wasted thermal energy = 9,000 J'.

Calculate the efficiency of the LED lamp.

Use the equation:

efficiency=useful energy transferred by the devicetotal energy supplied to the device \text{efficiency} = \frac{\text{useful energy transferred by the device}}{\text{total energy supplied to the device}} efficiency=total energy supplied to the deviceuseful energy transferred by the device​
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Efficiency and energy resources Questions

  1. GCSE
  2. /Physics
  3. /Efficiency and energy resources