HDE Section 1: Potential difference and work done (Electric Circuits) Flashcards Preview

Physics AS Level (Josh) > HDE Section 1: Potential difference and work done (Electric Circuits) > Flashcards

Flashcards in HDE Section 1: Potential difference and work done (Electric Circuits) Deck (11)
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1
Q

Define voltage?

A

Voltage is a general term referring to the amount of energy transferred per amount of charge.

2
Q

The potential difference of a component is the amount of ________ that the component transfers into other forms of _____, per coulomb of charge passing through.

A

The potential difference of a component is the amount of energy that the component transfers into other forms of energy, per coulomb of charge passing through.

3
Q

Define the electromotive force

A

The electromotive force (e.m.f.) of a source is the amount of energy it supplies to one coulomb of charge.

4
Q

The element of an electric kettle that takes a current of 12.5 A produces 540 kJ of thermal energy in 3 minutes.
How much charge passes through the element in these 3 minutes?
What is the potential difference across the ends of the element?

A

a) 2250C

b) 240V

5
Q

A 12V pump for a fountain in a garden pond can pump water up to a height of 0.80m at a rate of 4.8 litres per minute. How much work does the pump do per minute when raising the water to a height of 0.80 m? (You may assume that one litre of water has a mass of 1 kg.)
If the pump is 75% efficient, how much charge passes through the pump motor in one minute?
What current does the motor take when operating under these conditions?

A

a) 38 Jmin^-1
b) 4.2 C
c) 70mA

6
Q

Define power

A

Power is the rate of doing work. This could also be stated as the rate of energy transfer.

7
Q

True or False

Resistivity is a property of a material.

A

True

8
Q

Is resistance directly proportional to resistivity?

A

Yes

higher resistivity = higher resistance

9
Q

Is resistance inversely proportional to length?

A

Yes

longer wire = higher resistance

10
Q

Is resistance inversely proportional to area?

A

Yes

larger area = smaller resistance

11
Q

A wire is made of a metal with a resistivity of 2.85 x 10-8 Ωm. The wire is 0.32 m long and has a radius of 1.0 x 10^-3 m. The mass of the wire is 2.71 g.
Calculate the resistance of the wire.

A

2.9 x 10^-3 Ω

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