Page 152 - Physics Coursebook 2015 (A level)

Cambridge International AS Level Physics
End-of-chapter questions
1 Calculate the charge which passes through a lamp when there is a current of 150 mA for 40 minutes. [3]
2 A generator produces a current of 40 A. How long will it take for a total of 2000 C to flow through the output? [2]
3 In a lightning strike there is an average current of 30kA, which lasts for 2000μs. Calculate the charge which
is transferred in this process. [3]
4 a A lamp of resistance 15 Ω is connected to a battery of e.m.f. 4.5 V. Calculate the current in the lamp. [2] b Calculate the resistance of the filament of an electric heater which takes a current of 6.5 A when it is
connected across a mains supply of 230 V. [2] c Calculate the voltage which is require to drive a current of 2.4 A through a wire of resistance 3.5 Ω. [2]
5 A battery of e.m.f. 6 V produces a steady current of 2.4 A for 10 minutes. Calculate:
a the charge which it supplied [2]
b the energy that it transferred. [2]
6 Calculate the energy gained by an electron when it is accelerated through a potential difference of 50 kV.
(Charge on the electron = −1.6 × 10−19 C.) [2]
7 A woman has available 1 A, 3 A, 5 A, 10 A and 13 A fuses. Explain which fuse she should use for a 120 V,
450Whairdryer. [3]
8 Figure 9.17 shows the electrolysis of copper chloride. A
anode cathode
Cl– ions Cu2+ ions Figure 9.17 For End-of-chapter Question 8.
a i On a copy of the diagram, mark the direction of the conventional current in the electrolyte.
Label it conventional current. [1] ii Mark the direction of the electron flow in the connecting wires. Label this electron flow. [1]
b In a time period of 8 minutes, 3.6 × 1016 chloride (Cl−) ions are neutralised and liberated at the anode and 1.8 × 1016 copper (Cu2+) ions are neutralised and deposited on the cathode.
i Calculate the total charge passing through the electrolyte in this time. [2]
ii Calculate the current in the circuit. [2]
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