Practise

Question bank

Original exam-style questions, mapped to your syllabus. Answers are checked for mathematical equivalence and every attempt updates your mastery.

TopicSkillDifficulty

12 questions

SA-9702-CA3-0011 markL1 FoundationCalculatorTime constant

100

μF capacitor discharges through a

20

kΩ resistor. Calculate the time constant.

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SA-9702-CA3-0041 markL1 FoundationCalculatorTime constant

After one time constant, the charge on a discharging capacitor has fallen to about

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SA-9702-CA3-0051 markL1 FoundationCalculatorTime constant

Calculate the halving time for a capacitor discharging with

RC=5.0

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SA-9702-CA3-0101 markL1 FoundationCalculatorTime constant

Doubling the resistance in a discharging

RC

circuit

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SA-9702-CA3-0121 markL1 FoundationCalculatorTime constant

The product

RC

has units of

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SA-9702-CA3-0022 marksL2 StandardCalculatorExponential discharge

A capacitor at

12

V discharges with time constant

2.0

s. Calculate the p.d. after

3.0

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SA-9702-CA3-0032 marksL2 StandardCalculatorExponential discharge

For the same capacitor (

12

RC=2.0

s), calculate the time for the p.d. to fall to

3.0

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SA-9702-CA3-0061 markL2 StandardCalculatorExponential discharge

The discharge of a capacitor through a resistor is exponential because

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SA-9702-CA3-0071 markL2 StandardCalculatorExponential discharge

A graph of

\ln V

against

t

for a discharging capacitor has gradient

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SA-9702-CA3-0082 marksL2 StandardCalculatorExponential discharge

A capacitor discharges through a

10

kΩ resistor; the initial p.d. is

6.0

V. Calculate the initial current, in mA.

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SA-9702-CA3-0091 markL2 StandardCalculatorTime constant

A capacitor's p.d. falls to half its value in

1.4

s. Calculate its time constant.

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SA-9702-CA3-0113 marksL3 ExamCalculatorExponential discharge

470

μF capacitor charged to

9.0

V discharges through a resistor. After

20

s the p.d. is

2.0

V. Calculate the resistance, in kΩ.

Salam Academy Original Practice · Proposed mark scheme