GCSE Edexcel Physics Power: Some students investigate the ef

Question

Some students investigate the efficiency of electric motors.

(i) The students find that one electric motor has an efficiency of 60%.
Explain in terms of energy what is meant by an efficiency of 60%.

(ii) The students use some motors to lift weights.
The students measure the input power and output power of two motors.
Complete the sentence by putting a cross (X) in the box next to your answer.

The power of a motor is the rate at which it transfers

A  current
B  energy
C  voltage
D  charge

(iii) The first motor has a power rating of 20 W.
Calculate the energy supplied to the motor.

energy supplied to the motor = _____________________ J

(iv) In the second motor, the useful output power was 18 W when the input power was 24 W.
Calculate the efficiency of this motor.

efficiency = _____________________ %

(b) One of the students states that all of the energy supplied to a motor is transferred into other forms.
Complete the following sentence by putting a cross (X) in the box next to your answer.

renewable energy
conservation of energy
non-renewable energy
sustainable energy

Some students investigate the efficiency of electric motors - Edexcel - GCSE Physics - Question 2 - 2013 - Paper 1

Worked Solution & Example Answer:Some students investigate the efficiency of electric motors - Edexcel - GCSE Physics - Question 2 - 2013 - Paper 1

Explain in terms of energy what is meant by an efficiency of 60%.

Complete the sentence by putting a cross (X) in the box next to your answer.

Calculate the energy supplied to the motor.

Calculate the efficiency of this motor.

Complete the following sentence by putting a cross (X) in the box next to your answer.

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