Practise Electrical charge and current. 12 exam-style questions plus unlimited generated ones on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
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The current in the lamp is 0.40 A. Calculate the charge that flows through the lamp in 60 s. Use the equation: charge flow = current × time
24 C
Write down the equation that links charge flow (Q), current (I) and time (t).
Q = I t
State the instrument used to measure current, and how it is connected in a circuit.
An ammeter, connected in series.
A wire carries a current of 2 A. Explain what this means, in terms of charge.
2 coulombs of charge pass a given point in the wire every second.
State the unit of electric current.
Ampere (amp, A)
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy5 marks
A student sets up a simple circuit containing a cell, a switch and a lamp.
(a) Complete the sentence. Electric current is a flow of electrical ... Tick (✓) one box.[1]
charge.
energy.
power.
resistance.
(b) Which component in the circuit is the source of potential difference? Tick (✓) one box.[1]
the cell
the lamp
the switch
the wires
(c) The current in the lamp is 0.40 A. Calculate the charge that flows through the lamp in 60 s. Use the equation: charge flow = current × time[2]
(d) Give the unit of charge.[1]
Show the answer and mark scheme
(a)Answer: charge.
(b)Answer: the cell
(c)Answer: 24 C
Q = 0.40 × 60
Q = 24 (C)
(d)Answer: coulomb (C)
coulomb / C
Question 2Medium6 marks
A mobile phone battery is being charged.
(a) Write down the equation that links charge flow (Q), current (I) and time (t).[1]
(b) In 30 minutes, 2700 C of charge flows into the battery. Calculate the mean charging current.[3]
(c) In a different circuit, a lamp and a resistor are connected in series with a battery. The current in the lamp is 0.25 A. State the current in the resistor. Give a reason for your answer.[2]
Show the answer and mark scheme
(a)Answer: Q = I t
Q = I × t / charge flow = current × time
(b)Answer: 1.5 A
t = 1800 s
2700 = I × 1800
I = 1.5 (A)
(c)Answer: 0.25 A — the current is the same at every point in a single closed loop. A
0.25 (A)
the current is the same at any point in a single closed loop / series circuit
Question 3Hard8 marks
The current in a metal wire is a flow of electrons. The charge on one electron is 1.6 × 10−19 C.
(a) A current of 0.20 A flows in a wire for 5.0 minutes. Calculate the number of electrons that pass a point in the wire in this time.[4]
(b) The capacity of a torch battery is 3000 mA h. This means it can supply a current of 3000 mA for 1 hour. Calculate the total charge the battery can supply.[2]
(c) The torch draws a current of 0.45 A. Calculate how long a fully charged battery can power the torch. Give your answer in hours.[2]