AS AQA Phys Unit 1 (7)

What equation links power, current and resistance? (1 mark)

Power is equal to the current squared multiplied by resistance (1)

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If a heater has a power of 920W in normal operation with a p.d. of 230V what is the current? (2 marks) -use Data and Formulae Booklet

Power = p.d. x current therefore Current = power / p.d. (1) 920 / 230 = 4A (1)

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What is the equation of a straight line? (1 mark)

y = mx + c (1)

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Define terminal p.d. (1 mark)

Terminal p.d. is the electrical energy per unit charge delivered by a source (1)

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What is lost volts or lost p.d.? (2 marks)

The amount of voltage lost as heat energy, (1) when an emf passes through an internal resistance (1)

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What should the internal resistance for a HT or EHT power supply be and why? (2 marks)

The internal resistance should be very high (1) this is so only small amounts of current can be drawn, reducing the risk to the user (1)

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Other cards in this set

If a heater has a power of 920W in normal operation with a p.d. of 230V what is the current? (2 marks) -use Data and Formulae Booklet

Power = p.d. x current therefore Current = power / p.d. (1) 920 / 230 = 4A (1)

What is the equation of a straight line? (1 mark)

Define terminal p.d. (1 mark)

What is lost volts or lost p.d.? (2 marks)

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