Electricity - Paper 1 Flashcards Preview

AQA Physics Paper 1 11-A > Electricity - Paper 1 > Flashcards

Flashcards in Electricity - Paper 1 Deck (38)
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31

What happens when electrical current flows through a resistor?

Electrical energy is transformed into heat energy

32

What is a short circuit?

An electrical circuit that allows current to travel along unintended paths with no or very low resistance Resistance low = current very high. This will cause the battery to overheat

33

Why do lamps blow when they have just been turned on?

The lamp is cold so low resistance, high current flows - sometimes enough to melt the wire in the bulb

34

In a potential divider, what happens to voltage when two resistors are equal?

They share applied voltage equally

35

In a potential divider, a current passes through a resistor then through a thermistor. How does the voltage across each component change as temperature decreases?

The thermistor cools. The resistance of the thermistor rises, taking a larger share of input voltage. As the input from the battery is constant so output voltage rises across the fixed resistor.

36

In a potential divider, a current passes through a resistor then through a thermistor. How does the voltage across each component change as temperature increases?

The thermistor heats up. The resistance of the thermistor decreases, taking a smaller share of input voltage. As the input from the battery is constant so output voltage decreases across the fixed resistor.

37

In a potential divider, a current passes through a resistor then through an LDR. How does the voltage across each component change as light intensity increases?

If light intensity increases the resistance of the LDR decreases. The LDR will take a smaller share of the input voltage. As the input voltage from the battery is fixed the output voltage across the fixed resistor must increase.

38

In a potential divider, a current passes through a resistor then through an LDR. How does the voltage across each component change as light intensity decreases?

If light intensity decreases the resistance of the LDR increases. The LDR will take a larger share of the input voltage. As the input voltage from the battery is fixed the output voltage across the fixed resistor must decrease.