Electricity

What class are you in?

• 11X2A
• 11X2B
• 11Y2A
• 11Y2B
• Other

Which is the symbol for a thermistor?

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Which is true of a parallel circuit?

• The current is the same at each point in the parallel circuit.
• The circuit has a single closed loop.
• The potential difference across each lamp in a parallel circuit adds up to give the potential difference of a battery or cell.
• The currents in each separate branch add up to the total current that leaves the cell.

Which sentence regarding the electrical resistance of components is correct?

• The resistance of a light-dependent resistor increases as light level increases.
• The resistance of a thermistor increases as temperature increases.
• The resistance of a lamp increases as the current flowing through it increases.
• A diode’s forward resistance is very high.

Which statement about the resistance of a component is true?

• Two fixed resistors in parallel will have double the total resistance of a single resistor.
• If two resistors are arranged in parallel, the total resistance is increased because the total current decreases but the potential difference is the same.
• If two resistors are arranged in series, the total resistance is decreased because the current is greater but the potential difference is the same.
• The total resistance is equal to the potential difference across it divided by the total current flowing through it.

Which graph is characteristic of a diode?

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Which graph is characteristic of a filament lamp?

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Which statement about current, charge, and time is correct?

• A charger rated 2600 mAh will mean that 2600 C flows when the charger discharges.
• There is a current of 18 000 A in a lamp if a charge of 18 000 C flows in 1 hour
• The current through you when you hold the ends of a battery is about 10 µA, which means a charge of 30 µC flows in 3 seconds.
• A current of 5000 A in a lightning strike means 1000 C of charge flows in 5 s.

Which of these expressions gives the flow of charge, Q, in an electric circuit?

• Current/time
• Current x time
• Time/Current

A charge of 12 C passes a point in 4 s. What is the current? (Don't forget the unit)

(a)