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For people studying A-level Physics (OCR).
Published
June 17, 2019
...
June 17, 2019
· 79 takers
School & Academics
Science & Tech
Physics
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School
Ocr
A Levels
Science
Energy
Power
Resistance
Electricity
Electronics
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Physics Revision: Energy, Power and Resistance
Leucistic Puffin
1
12
What is a battery?
Two or more cells connected in series
A cell
A high-power cell
Two or more cells connected in parallel
2
12
What is potential difference?
A measure of the current carried by electrons
A measure of the transfer of energy by charge carriers
A measure of the charge in a circuit
A.measure of the strength of a circuit
3
12
What is the unit of electromotive force (EMF)?
Newtons
Amperes
Volts
Joules
4
12
Define resistance.
Potential difference across a component divided by the current in said component
Potential difference across a component multiplied by the current in said component.
Current in a component divided by potential difference across said component.
The difference between potential difference and current.
5
12
What is Ohm's law?
For a metallic conductor kept at constant temperature, the current in the wire is inversely proportional to the pd across its ends.
For a metallic conductor kept at constant temperature, the current in the wire is inversely proportional to the square of the pd across its ends.
For a metallic conductor kept at constant temperature, the current in the wire is equal to the pd across its ends.
For a metallic conductor kept at constant temperature, the current in the wire is directly proportional to the pd across its ends.
6
12
What does the IV characteristic of a filament lamp look like?
A quadratic curve
An S-shaped curve
A straight line through the origin
A straight line
7
12
Why are diodes so useful?
They have no resistance.
The amount of current in them is easy to control.
They do not overheat.
They only allow current in one direction.
8
12
Define resistivity.
(Resistance x length)/cross-sectional area
(Length x cross-sectional area)/resistance
(Resistance/cross-sectional area) x length
(Resistance x cross-sectional area)/length
9
12
What happens to a thermistor as temperature increases?
Resistance stays constant
Resistance doubles
Resistance decreases
Resistance increases
10
12
What happens to an LDR as light intensity increases?
Resistance decreases.
Resistance increases.
Resistance stays constant.
Resistance halves.
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12
What is the equation for electrical power?
Potential difference x resistance
Potential difference/resistance
Potential difference x current
Potential difference/current
12
12
What is the equation for electrical energy?
Energy = voltage x current x resistance
Energy = Power x time
Energy = Power/time
Energy = mgh
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