Electric current — Paper 1 · A Level Physics 9702

35 The diagram shows a junction in a circuit where three wires P, Q and R meet. The currents in P and Q are 1 A and 3 A respectively, in the directions shown. Q 3 A 1 A P R How many coulombs of charge pass a given point in wire R in 5 seconds? A 0.4 B 0.8 C 2 D 10

1 marks

Answer: D

This question in 9702/11 Oct/Nov 2004

31 The current in the circuit is 4.8 A. R X Y What is the rate of flow and the direction of flow of electrons through the resistor R? A 3.0 × 1019 s–1 in direction X to Y B 6.0 × 1018 s–1 in direction X to Y C 3.0 × 1019 s–1 in direction Y to X D 6.0 × 1018 s–1 in direction Y to X

1 marks

Answer: C

This question in 9702/11 May/June 2006

31 Four point charges, each of charge Q, are placed on the edge of an insulating disc of radius r. The frequency of rotation of the disc is f. Q r Q Q Q What is the equivalent electric current at the edge of the disc? 4 Q 2 Qf A 4Qf B C 8πrQf D f π r

1 marks

Answer: A

This question in 9702/11 Oct/Nov 2006

32 The current in a resistor is 8.0 mA. What charge flows through the resistor in 0.020 s? A 0.16 mC B 1.6 mC C 4.0 mC D 0.40 C

1 marks

Answer: A

This question in 9702/11 May/June 2007

33 A total charge of 100 C flows through a 12 W light bulb in a time of 50 s. What is the potential difference across the bulb during this time? A 0.12 V B 2.0 V C 6.0 V D 24 V

1 marks

Answer: C

This question in 9702/11 May/June 2008

35 The potential difference across a resistor is 12 V. The current in the resistor is 2.0 A. 4.0 C passes through the resistor. What is the energy transferred and the time taken? energy / J time / s A 3.0 2.0 B 3.0 8.0 C 48 2.0 D 48 8.0

1 marks

Answer: C

This question in 9702/11 May/June 2008

34 The charge that a fully-charged 12 V car battery can supply is 100 kC. The starter motor of the car requires a current of 200 A for an average period of 2.0 s. The battery does not recharge because of a fault. What is the maximum number of times the starter motor of the car can be used? A 21 B 25 C 42 D 250

1 marks

Answer: D

This question in 9702/11 Oct/Nov 2008

30 Which amount of charge, flowing in the given time, will produce the largest current? charge / C time / s A 4 1 4 B 4 1 C 1 4 D 1 4 4 Space for working

1 marks

Answer: A

This question in 9702/11 May/June 2009

3 The graph shows two current-voltage calibration curves for a solar cell exposed to different light intensities. intensity = 1000 W m–2 3.0 current / A 2.0 1.0 intensity = 100 W m–2 0 0 0.1 0.2 0.3 0.4 0.5 0.6 voltage / V current at 1000 W m _ 2 At zero voltage, what is the ratio ? current at 100 W m _ 2 A 1.1 B 4.7 C 8.0 D 10 Space for working

1 marks

Answer: B

This question in 9702/11 Oct/Nov 2009

34 The diagram shows the symbol for a wire carrying a current I. I X Y What does this current represent? A the amount of charge flowing past a point in XY per second B the number of electrons flowing past a point in XY per second C the number of positive ions flowing past a point in XY per second D the number of protons flowing past a point in XY per second Space for working

1 marks

Answer: A

This question in 9702/11 Oct/Nov 2009

2 The graph shows two current-voltage calibration curves for a solar cell exposed to different light intensities. intensity = 1000 W m–2 3.0 current / A 2.0 1.0 intensity = 100 W m–2 0 0 0.1 0.2 0.3 0.4 0.5 0.6 voltage / V current at 1000 W m _ 2 At zero voltage, what is the ratio ? current at 100 W m _ 2 A 1.1 B 4.7 C 8.0 D 10 Space for working

1 marks

Answer: B

This question in 9702/12 Oct/Nov 2009

33 The diagram shows the symbol for a wire carrying a current I. I X Y What does this current represent? A the amount of charge flowing past a point in XY per second B the number of electrons flowing past a point in XY per second C the number of positive ions flowing past a point in XY per second D the number of protons flowing past a point in XY per second Space for working

1 marks

Answer: A

This question in 9702/12 Oct/Nov 2009

31 When there is no current in a wire, which statement about the conduction electrons in that wire is correct? A Electrons in the wire are moving totally randomly within the wire. B Equal numbers of electrons move at the same speed, but in opposite directions, along the wire. C No current is flowing therefore the electrons in the wire are stationary. D No current is flowing therefore the electrons in the wire are vibrating around a fixed point.

1 marks

Answer: A

This question in 9702/12 Oct/Nov 2010

32 The current in the circuit shown is 4.8 A. R X Y What is the direction of flow and the rate of flow of electrons through the resistor R? direction of flow rate of flow A X to Y 3.0 × 1019 s–1 B X to Y 6.0 × 1018 s–1 C Y to X 3.0 × 1019 s–1 D Y to X 6.0 × 1018 s–1

1 marks

Answer: C

This question in 9702/13 Oct/Nov 2010

31 A copper wire of cross-sectional area 2.0 mm2 carries a current of 10 A. How many electrons pass through a given cross-section of the wire in one second? A 1.0 × 101 B 5.0 × 106 C 6.3 × 1019 D 3.1 × 1025

1 marks

Answer: C

This question in 9702/11 May/June 2011

32 A copper wire of cross-sectional area 2.0 mm2 carries a current of 10 A. How many electrons pass through a given cross-section of the wire in one second? A 1.0 × 101 B 5.0 × 106 C 6.3 × 1019 D 3.1 × 1025

1 marks

Answer: C

This question in 9702/13 May/June 2011

35 Which statement is not valid? A Current is the speed of the charged particles that carry it. B Electromotive force (e.m.f.) is the energy converted to electrical energy from other forms, per unit charge. C The potential difference (p.d.) between two points is the work done in moving unit charge from one point to the other. D The resistance between two points is the p.d. between the two points, per unit current. Space for working

1 marks

Answer: A

This question in 9702/11 Oct/Nov 2011

32 A charge of 8.0 C passes through a resistor of resistance 30 Ω at a constant rate in a time of 20 s. What is the potential difference across the resistor? A 0.40 V B 5.3 V C 12 V D 75 V Space for working

1 marks

Answer: C

This question in 9702/12 Oct/Nov 2011

34 Which statement is not valid? A Current is the speed of the charged particles that carry it. B Electromotive force (e.m.f.) is the energy converted to electrical energy from other forms, per unit charge. C The potential difference (p.d.) between two points is the work done in moving unit charge from one point to the other. D The resistance between two points is the p.d. between the two points, per unit current.

1 marks

Answer: A

This question in 9702/13 Oct/Nov 2011

32 When will 1 C of charge pass a point in an electrical circuit? A when 1 A moves through a potential difference of 1 V B when a power of 1 W is used for 1 s C when the current is 5 mA for 200 s D when the current is 10 A for 10 s Space for working

1 marks

Answer: C

This question in 9702/12 May/June 2012

33 Two copper wires of the same length but different diameters carry the same current. Which statement about the flow of charged particles through the wires is correct? A Charged particles are provided by the power supply. Therefore the speed at which they travel depends only on the voltage of the supply. B The charged particles in both wires move with the same average speed because the current in both wires is the same. C The charged particles move faster through the wire with the larger diameter because there is a greater volume through which to flow. D The charged particles move faster through the wire with the smaller diameter because it has a larger potential difference applied to it.

1 marks

Answer: D

This question in 9702/12 May/June 2012

32 The potential difference between point X and point Y in a circuit is 20 V. The time taken for charge carriers to move from X to Y is 15 s. In this time, the energy of the charge carriers changes by 12 J. What is the current between X and Y? A 0.040 A B 0.11 A C 9.0 A D 25 A Space for working

1 marks

Answer: A

This question in 9702/11 Oct/Nov 2012

2 Which unit is equivalent to the coulomb? A ampere per second B joule per volt C watt per ampere D watt per volt

1 marks

Answer: B

This question in 9702/13 Oct/Nov 2013

32 The current in a component is reduced uniformly from 100 mA to 20 mA over a period of 8.0 s. What is the charge that flows during this time? A 160 mC B 320 mC C 480 mC D 640 mC Space for working

1 marks

Answer: C

This question in 9702/13 Oct/Nov 2013

33 An electric current is passed from a thick copper wire through a section of thinner copper wire before entering a second thick copper wire as shown. current thinner copper wire copper wire copper wire Which statement about the current and the speed of electrons in the wires is correct? A The current and the speed of the electrons in the thinner wire are both less than in the thicker copper wires. B The current and the speed of the electrons is the same in all the wires. C The current is the same in all the wires but the speed of the electrons in the thinner wire is greater than in the thicker wires. D The current is the same in all the wires but the speed of the electrons in the thinner wire is less than in the thicker wire.

1 marks

Answer: C

This question in 9702/13 Oct/Nov 2013

35 The potential difference across a component in a circuit is 2.0 V. How many electrons must flow through this component in order for it to be supplied with 4.8 J of energy? A 2.6 × 1018 B 1.5 × 1019 C 3.0 × 1019 D 6.0 × 1019 Space for working

1 marks

Answer: B

This question in 9702/11 May/June 2014

33 Two wires P and Q made of the same material and of the same length are connected in parallel to the same voltage supply. Wire P has diameter 2 mm and wire Q has diameter 1 mm. What is the ratio current in P ? current in Q 1 1 2 4 A B C D 4 2 1 1

1 marks

Answer: D

This question in 9702/13 May/June 2014

35 The charge that an electric battery can deliver is specified in ampere-hours. For example, a battery of capacity 40 ampere-hours could supply, when fully charged, 0.2 A for 200 hours. What is the maximum energy that a fully charged 12 V, 40 ampere-hour battery could supply? A 1.7 kJ B 29 kJ C 1.7 MJ D 29 MJ

1 marks

Answer: C

This question in 9702/11 May/June 2015

31 Which unit is not used in either the definition of the coulomb or the definition of the volt? A ampere B joule C ohm D second

1 marks

Answer: C

This question in 9702/12 May/June 2015

33 Which statement is not valid? A Current is the speed of the charged particles that carry it. B Electromotive force (e.m.f.) is the energy converted to electrical energy from other forms per unit charge. C The potential difference (p.d.) between two points is the work done per unit charge when moving charge from one point to the other. D The resistance between two points is the p.d. between the two points per unit current.

1 marks

Answer: A

This question in 9702/12 May/June 2015

33 Which unit is equivalent to a coulomb (C)? A A s B Ω s C V s D W s

1 marks

Answer: A

This question in 9702/12 Oct/Nov 2015

30 An electrical conductor has a resistance of 5.6 kΩ. A potential difference (p.d.) of 9.0 V is applied across its ends. How many electrons pass a point in the conductor in one minute? A 6.0 × 1020 B 1.0 × 1019 C 6.0 × 1017 D 1.0 × 1016

1 marks

Answer: C

This question in 9702/12 Feb/March 2016

33 A 12 V battery is charged for 20 minutes by connecting it to a source of electromotive force (e.m.f.). The battery is supplied with 7.2 × 104 J of energy in this time. How much charge flows through the battery? A 5.0 C B 60 C C 100 C D 6000 C

1 marks

Answer: D

This question in 9702/12 Feb/March 2016

36 In deriving a formula for the combined resistance of three different resistors in series, Kirchhoff’s laws are used. Which physics principle is involved in this derivation? A the conservation of charge B the direction of the flow of charge is from negative to positive C the potential difference across each resistor is the same D the current varies in each resistor, in proportion to the resistor value

1 marks

Answer: A

This question in 9702/12 Feb/March 2016

35 The charge that a fully charged 12 V car battery can supply is 100 kC. The starter motor of the car requires a current of 200 A for an average period of 2.0 s. The battery does not recharge because of a fault. What is the maximum number of times the starter motor of the car can be used? A 21 B 25 C 42 D 250

1 marks

Answer: D

This question in 9702/12 May/June 2016

31 In an electrolyte, the electric current is carried by charged particles (ions) in solution. What is not a possible value for the charge on an ion in solution? A – 4.8 × 10–19 C B +1.6 × 10–19 C C +3.2 × 10–19 C D +4.0 × 10–19 C

1 marks

Answer: D

This question in 9702/13 May/June 2016

34 A thick copper wire is connected to a thin copper wire in series with a cell, as shown. thick wire thin wire What is significantly less in the thick wire than in the thin wire? A the charge passing a point per unit time B the drift speed of the electrons C the number density of the free electrons D the number of free electrons passing a point per unit time

1 marks

Answer: B

This question in 9702/11 Oct/Nov 2016

34 A thick copper wire is connected to a thin copper wire in series with a cell, as shown. thick wire thin wire What is significantly less in the thick wire than in the thin wire? A the charge passing a point per unit time B the drift speed of the electrons C the number density of the free electrons D the number of free electrons passing a point per unit time

1 marks

Answer: B

This question in 9702/13 Oct/Nov 2016

32 An electric current I is given in the list of formulae on page 3 as I = Anvq. What do each of the symbols represent for an electric current in a metal wire? A n v q A area of number of free voltage charge of cross-section electrons each molecule B area of number of free average charge of cross-section electrons per drift speed each electron unit volume of electrons C current number of free average charge of electrons drift speed each molecule of electrons D current number of free voltage charge of electrons per each electron unit volume

1 marks

Answer: B

This question in 9702/12 Feb/March 2017

32 The diagram shows the symbol for a wire carrying a current I. I What does this current represent? A the charge flowing past a point in the wire per unit time B the number of electrons flowing past a point in the wire per unit time C the number of positive ions flowing past a point in the wire per unit time D the number of protons flowing past a point in the wire per unit time

1 marks

Answer: A

This question in 9702/11 May/June 2017

32 The current in a circuit component is 2.00 µA. How many electrons pass through the component each second? A 1.25 × 1013 B 1.25 × 1016 C 1.25 × 1019 D 1.25 × 1025

1 marks

Answer: A

This question in 9702/12 May/June 2017

31 Two metal plates are a distance of 30 cm apart in a vacuum. A current exists between the two plates consisting of electrons moving at a constant speed of 1.5 × 106 m s–1. At any instant, there is always just one electron travelling between the plates. What is the current between the plates? A 3.2 × 10–26 A B 8.0 × 10–13 A C 1.6 × 10–12 A D 2.0 × 10–7 A

1 marks

Answer: B

This question in 9702/13 May/June 2017

33 The current in the circuit shown is 3.2 mA. R X Y What are the direction of flow and the rate of flow of electrons through the resistor R? direction of flow rate of flow / s–1 A X to Y 2.0 × 1016 B X to Y 5.1 × 10–22 C Y to X 2.0 × 1016 D Y to X 5.1 × 10–22

1 marks

Answer: C

This question in 9702/11 Oct/Nov 2017

33 Two copper wires are joined together and carry a current, as shown. current current wire P wire Q diameter d diameter 2d Wire P has diameter d and wire Q has diameter 2d. average drift speed of the free electrons in wire P What is the ratio ? average drift speed of the free electrons in wire Q A 1 B 1 C 2 D 4 4 2

1 marks

Answer: D

This question in 9702/12 Oct/Nov 2017

33 The number density of conduction electrons in copper is 8.0 × 1028 m–3. What is the average drift speed of electrons in a copper wire of diameter 0.42 mm when the current in the wire is 0.57 A? A 8.0 × 10–11 m s–1 B 3.2 × 10–10 m s–1 C 8.0 × 10–5 m s–1 D 3.2 × 10–4 m s–1

1 marks

Answer: D

This question in 9702/13 Oct/Nov 2017

35 Charge carriers, each of charge q, move along a wire of fixed length. The number density of the charge carriers in the wire is n. What is also required, for this wire, to determine the average drift velocity of the charge carriers in terms of n and q? A current per unit of cross-sectional area B potential difference per unit of length C resistance and cross-sectional area D resistivity and length

1 marks

Answer: A

This question in 9702/12 Feb/March 2018

30 The current I in a metal wire is given by the expression shown. I = Anvq What does the symbol n represent? A the number of atoms per unit volume of the metal B the number of free electrons per atom in the metal C the number of free electrons per unit volume of the metal D the total number of electrons per unit volume of the metal

1 marks

Answer: C

This question in 9702/11 May/June 2018

29 What is a possible charge on a particle? A 6.40 × 10–20 C B 4.00 × 10–19 C C 1.12 × 10–18 C D 9.11 × 10–18 C

1 marks

Answer: C

This question in 9702/13 May/June 2018

30 A slice of germanium of cross-sectional area 1.0 cm2 carries a current of 56 µA. The number density of charge carriers in the germanium is 2.0 × 1013 cm–3. Each charge carrier has a charge equal to the charge on an electron. slice of germanium area 1.0 cm2 current 56 µA What is the average drift velocity of the charge carriers in the germanium? A 0.18 m s–1 B 18 m s–1 C 180 m s–1 D 1800 m s–1

1 marks

Answer: A

This question in 9702/13 May/June 2018

33 When there is a current of 5.0 A in a copper wire, the average drift velocity of the free electrons is 8.0 × 10–4 m s–1. What is the average drift velocity in a different copper wire that has twice the diameter and a current of 10.0 A? A 4.0 × 10–4 m s–1 B 8.0 × 10–4 m s–1 C 1.6 × 10–3 m s–1 D 3.2 × 10–3 m s–1

1 marks

Answer: A

This question in 9702/11 Oct/Nov 2018

33 Which two units are used to define the coulomb? A ampere and second B ampere and volt C volt and ohm D volt and second

1 marks

Answer: A

This question in 9702/12 Oct/Nov 2018

32 The current I in a copper wire can be calculated using the equation shown. I = Anvq What does the symbol v represent? A the average drift velocity of the charge carriers B the instantaneous velocity of the charge carriers C the voltage applied across the wire D the volume of the wire

1 marks

Answer: A

This question in 9702/13 Oct/Nov 2018

32 The electric current in a wire may be calculated using the equation I = Anvq. Which statement is not correct? A n is the number of charge carriers per unit volume of the wire. B nA is the number of charge carriers per unit length of the wire. C q is the charge of each charge carrier. D v is the velocity of each charge carrier.

1 marks

Answer: D

This question in 9702/12 Feb/March 2019

32 In an electrolyte, the electric current is carried by charged particles (ions) in solution. What is not a possible value for the charge on an ion in solution? A – 4.8 × 10–19 C B +1.6 × 10–19 C C +3.2 × 10–19 C D +4.0 × 10–19 C

1 marks

Answer: D

This question in 9702/11 May/June 2019

33 A length of wire is connected into a circuit. area A area A 1 2 S R The area of the cross-section of the wire changes from A at R to 2 1 A at S. There is a constant current in the wire. Charge Q passes R in time t. What is the charge passing point S in the same time t ? A 1 Q B Q C Q 2 D 2Q 2

1 marks

Answer: B

This question in 9702/12 May/June 2019

30 A metal plate of uniform thickness is connected to a cell as shown. metal plate viewed from electron above flow Electrons move clockwise around the circuit. Which statement about the metal plate is correct? A The average drift speed of the conduction electrons decreases as they move from right to left through the plate. B The average drift speed of the conduction electrons increases as they move from right to left through the plate. C The number density of the conduction electrons decreases from right to left through the plate. D The number density of the conduction electrons increases from right to left through the plate.

1 marks

Answer: B

This question in 9702/11 Oct/Nov 2019

31 The diagram shows the direction of the current in a metal block. The charge carriers enter the block through the face PQRS and leave the block through the opposite face. P Q S x y current R x The number density of charge carriers is n. Each charge carrier has charge e. The average drift speed of the charge carriers is v. Which expression gives the current in the block? A envx2 B envxy C envx3y2 D envx4y

1 marks

Answer: B

This question in 9702/11 Oct/Nov 2019

31 When the current in a wire is 5.0 A, the average drift speed of the conduction electrons in the wire is 7.4 × 10–4 m s–1. Which row gives a possible cross-sectional area and number of conduction electrons per unit volume for this wire? number of conduction cross-sectional area / m2 electrons per unit volume / m–3 A 7.2 × 10–7 1.2 × 1028 B 7.2 × 10–7 5.9 × 1028 C 2.3 × 10–6 7.3 × 1026 D 2.3 × 10–6 3.7 × 1027

1 marks

Answer: B

This question in 9702/12 Oct/Nov 2019

33 There is a current in a resistor for an unknown time. Which two quantities can be used to calculate the energy dissipated by the resistor? A the current in the resistor and the potential difference across the resistor B the resistance of the resistor and the current in the resistor C the total charge passing through the resistor and the potential difference across the resistor D the total charge passing through the resistor and the resistance of the resistor

1 marks

Answer: C

This question in 9702/12 Oct/Nov 2019

33 A metal electrical conductor has a resistance of 5.6 kΩ. A potential difference (p.d.) of 9.0 V is applied across its ends. How many electrons pass a point in the conductor in one minute? A 6.0 × 1020 B 1.0 × 1019 C 6.0 × 1017 D 1.0 × 1016

1 marks

Answer: C

This question in 9702/13 Oct/Nov 2019

32 Electrons move in a vacuum from one metal plate to another metal plate. As a result of this, there is an electric current of 48 µA between the two plates. How many electrons are emitted by the first plate in a time of 5.0 minutes? A 1.4 × 104 B 1.5 × 1015 C 1.8 × 1016 D 9.0 × 1016

1 marks

Answer: D

This question in 9702/12 Feb/March 2020

33 The current in the circuit shown is 3.2 mA. R X Y What are the direction of flow and the rate of flow of electrons through the resistor R? direction of flow rate of flow / s–1 A X to Y 2.0 × 1016 B X to Y 5.1 × 10–22 C Y to X 2.0 × 1016 D Y to X 5.1 × 10–22

1 marks

Answer: C

This question in 9702/11 May/June 2020

33 The number density of free electrons in copper is 8.0 × 1028 m–3. A copper wire has diameter 0.42 mm. What is the average drift speed of the free electrons in the wire when the current in the wire is 0.57 A? A 8.0 × 10–11 m s–1 B 3.2 × 10–10 m s–1 C 8.0 × 10–5 m s–1 D 3.2 × 10–4 m s–1

1 marks

Answer: D

This question in 9702/12 May/June 2020

33 The unit of electric charge is the coulomb. What is meant by 1 coulomb? A the charge passing a point in 1 second when a current produces 1 joule of work B the charge passing a point in 1 second when a current produces 1 watt of power C the charge passing a point in 1 second when there is a current of 1 ampere D the charge passing a point in 1 second when there is 1 ohm of resistance

1 marks

Answer: C

This question in 9702/13 May/June 2020

34 Two copper wires are joined together and carry a current, as shown. current current wire P diameter d wire Q diameter 2d Wire P has diameter d and wire Q has diameter 2d. average drift speed of the free electrons in wire P What is the ratio ? average drift speed of the free electrons in wire Q A 1 B 1 C 2 D 4 4 2

1 marks

Answer: D

This question in 9702/13 May/June 2020

32 Free electrons flow along a copper wire X of radius 5.0  10–5 m with an average drift speed of 2.8  10–2 m s–1. The current in the wire is 3.0 A. There is a current of 2.0 A in a copper wire Y of radius 1.0  10–4 m. What is the average drift speed of the free electrons in copper wire Y? A 4.7  10–3 m s–1 B 9.3  10–3 m s–1 C 1.1  10–2 m s–1 D 1.9  10–2 m s–1

1 marks

Answer: A

This question in 9702/11 Oct/Nov 2020

33 Four point charges, each of charge Q, are placed on the edge of an insulating disc of radius r. The disc rotates at a rate of n revolutions per unit time. Q r Q Q Q What is the equivalent electric current at the edge of the disc? A 4Qn B 4Q n C 8rQn D 2Qn π r

1 marks

Answer: A

This question in 9702/12 Oct/Nov 2020

33 Two resistors R1 and R2 are made from wire of the same material. They are connected in parallel to each other in a circuit, as shown. R1 R2 The diameter of R2 is half the diameter of R1. The resistance of R2 is three times the resistance of R1. average drift speed of free electrons in R What is the value of the ratio average drift speed of free electrons inR ? 1 2 3 3 1 1 A 2 B 4 C 6 D 12

1 marks

Answer: B

This question in 9702/13 Oct/Nov 2020

32 The current I in a metal wire is given by the equation I = Anvq. What does the symbol n represent? A the number of charge carriers in the wire B the number of charge carriers per unit cross-sectional area of the wire C the number of charge carriers per unit length of the wire D the number of charge carriers per unit volume of the wire

1 marks

Answer: D

This question in 9702/12 Feb/March 2021

32 Which two units are used to define the coulomb? A ampere and second B ampere and volt C volt and ohm D volt and second

1 marks

Answer: A

This question in 9702/11 May/June 2021

33 A wire has a length of 12 cm and contains a total of 5.1  1022 free electrons. When a potential difference is applied across the ends of the wire, the free electrons move with an average drift speed of 4.0  10–6 m s–1. What is the current in the wire? A 0.0027 A B 0.0039 A C 0.27 A D 0.39 A

1 marks

Answer: C

This question in 9702/13 May/June 2021

32 The current I in a wire is given by the equation I = nAvq where n is the number density of the free electrons, A is the cross-sectional area of the wire, v is the average drift velocity of the free electrons and q is the charge of an electron. Which relationship is not used in the derivation of this equation? A charge = current  time B distance = speed  time C number = number density  area D volume = length  area

1 marks

Answer: C

This question in 9702/11 Oct/Nov 2021

33 A lightning strike transfers 1  1020 electrons past a point in a time of 30 s. What is the average current during the lightning strike? A 0.5 mA B 0.5 A C 500 A D 500 kA

1 marks

Answer: D

This question in 9702/13 Oct/Nov 2021

29 For a current-carrying wire, the current can be calculated using the equation shown. I = Anvq What is the meaning of n? A the number of charge carriers in the wire B the number of charge carriers multiplied by the volume of the wire C the number of charge carriers per unit length of the wire D the number of charge carriers per unit volume of the wire

1 marks

Answer: D

This question in 9702/12 Feb/March 2022

30 The number of free electrons passing a point in a wire in 24 hours is 6.0  1023. What is the average current in the wire? A 6.3 pA B 1.1 A C 67 A D 4.0 kA

1 marks

Answer: B

This question in 9702/12 Feb/March 2022

31 A straight copper wire of diameter 0.42  10–3 m has a number density of free electrons of 8.5  1028 m–3. In a given time interval, a charge of 0.15 C moves through the wire. What is the average displacement of the free electrons along the wire in this time interval? A 3.3  10–8 m B 2.0  10–5 m C 8.0  10–5 m D 2.5  10–4 m

1 marks

Answer: C

This question in 9702/11 May/June 2022

31 The diagram shows a metal block. I I c a b The block has sides of length a, b and c as shown, and its volume is V. Each charge carrier has a charge –q and the number density of the charge carriers in the metal is n. It takes each charge carrier an average time of t to pass through the block. What is an expression for the current I ? I = nqV I = nqbc A I = nqabc B C D I = nqaV t t

1 marks

Answer: B

This question in 9702/12 May/June 2022

31 A length of wire RS has a circular cross-section. area A area A 2 S R At end R of the wire, the cross-sectional area is A. A . At end S of the wire, the cross-sectional area is 2 Charge Q takes time t to pass through end R of the wire. There is a constant electric current in the wire. t ? How much charge will pass through end S in a time interval of 4 Q Q Q A B C D Q 8 4 2

1 marks

Answer: B

This question in 9702/11 Oct/Nov 2022

31 A nichrome wire has a resistance of 15  and a diameter of 3.0 mm. The number density of the free electrons in nichrome is 9.0  1028 m–3. A potential difference (p.d.) of 6.0 V is applied between the ends of the wire. What is the average drift speed of the free electrons in the wire? A 9.8  10–7 m s–1 B 3.9  10–6 m s–1 C 6.1  10–6 m s–1 D 2.5  10–5 m s–1

1 marks

Answer: B

This question in 9702/12 Oct/Nov 2022

30 There is an electric current in a copper wire. Which statement describing the average drift speed of the charge carriers in the wire is correct? A It is nearly 3  108 m s–1. B It is proportional to the cross-sectional area of the wire. C It is proportional to the length of the wire. D It is proportional to the magnitude of the current.

1 marks

Answer: D

This question in 9702/13 Oct/Nov 2022

30 A wire carries a current of 0.10 µA. The potential difference across the wire is 10 mV. How much energy is dissipated by the wire in a time of 10 s? A 1.0 pJ B 10 pJ C 1.0 nJ D 10 nJ

1 marks

Answer: D

This question in 9702/12 Feb/March 2023

30 The electric current in a metal wire is 4.0 mA. How many electrons pass a fixed point in the wire in a time of 10 hours? A 2.5  1017 B 2.5  1020 C 9.0  1020 D 9.0  1023

1 marks

Answer: C

This question in 9702/11 May/June 2023

30 Which charge can be carried by a charge carrier? A 1.1  10–19 C B 4.0  10–19 C C 4.8  10–19 C D 9.1  10–19 C

1 marks

Answer: C

This question in 9702/12 May/June 2023

30 A metal wire is connected between the terminals of a cell so that there is a current in the wire. Which statement is correct? A Negatively charged electrons in the wire move from the negative terminal to the positive terminal. B Negatively charged nuclei in the wire move from the negative terminal to the positive terminal. C Positively charged electrons in the wire move from the positive terminal to the negative terminal. D Positively charged nuclei in the wire move from the positive terminal to the negative terminal.

1 marks

Answer: A

This question in 9702/13 May/June 2023

30 A fine mist of oil droplets is sprayed into air. As the oil droplets leave the nozzle of the spraying device they can become electrically charged. What is not a possible value for the charge on an oil droplet? A zero B 1.0 × 10–19 C C 4.8 × 10–19 C D 8.0 × 10–19 C

1 marks

Answer: B

This question in 9702/12 Oct/Nov 2023

2 In an electric circuit, an ammeter reads 2 A. In a second circuit, the ammeter reads 1 mA. How many times larger is the current in the second circuit compared with the current in the first circuit? A 500 B 5000 C 500 000 D 5 000 000

1 marks

Answer: A

This question in 9702/13 Oct/Nov 2023

36 A radioactive source produces a beam of -particles in a vacuum. The average current caused by the -particles in the beam is 1.5  10–9 A. The beam is incident on a metal target. What is the average number of -particles hitting the metal target in a time of 3.0 s? A 4.7  109 B 9.4  109 C 1.4  1010 D 2.8  1010

1 marks

Answer: C

This question in 9702/12 Feb/March 2024

37 The charge carriers in a metal wire are free electrons. Which statement about the charge of each free electron is correct? A The magnitude of the charge increases with the potential difference across the wire. B The magnitude of the charge is zero unless there is a potential difference across the wire. C The sign and magnitude of the charge do not depend on the potential difference across the wire. D The sign of the charge depends on the potential difference across the wire. 2 e

1 marks

Answer: C

This question in 9702/12 Feb/March 2024

32 A cylindrical wire has cross-sectional area A and number density of free electrons n. The wire has current I and the free electrons have average drift speed v. A second cylindrical wire has cross-sectional area 0.5A and number density of free electrons 2n. In this wire, the free electrons have average drift speed 2v. What is the current in the second wire? A 0.5I B I C 2I D 4I

1 marks

Answer: C

This question in 9702/12 May/June 2024

33 An electric current is formed by moving charge carriers. What is not a possible charge on a charge carrier? A – 4.8  10–19 C B –2.4  10–19 C C +1.6  10–19 C D +3.2  10–19 C

1 marks

Answer: B

This question in 9702/12 May/June 2024

32 There is a current in a resistor for a short time interval. Which statement about the total charge that passes through the resistor is correct? A It can take any value. B It is an integer multiple of the elementary charge. C It is the elementary charge. D It is the rate of flow of the current.

1 marks

Answer: B

This question in 9702/12 Oct/Nov 2024

34 An electric current of 12 A is in a wire of length 0.35 m. The average drift speed of the free electrons (charge carriers) in the wire is 5.0  10–4 m s–1. How many free electrons are in the wire? A 1.3  1016 B 5.3  1022 C 1.5  1023 D 4.3  1023

1 marks

Answer: B

This question in 9702/12 Oct/Nov 2024

31 What is an electric current? A a flow of charge carriers B a flow of energy C an electron D the charge on a particle

1 marks

Answer: A

This question in 9702/13 Oct/Nov 2024

32 A wire of diameter d is connected into an electric circuit. There is a current I in the wire and the charge carriers have an average drift speed v. The wire is replaced with a new wire of the same material but with a diameter 0.5d. The current is adjusted so that the charge carriers in the new wire have an average drift speed 3v. What is the current in the new wire? A 0.75I B 1.5I C 6I D 12I

1 marks

Answer: A

This question in 9702/13 Oct/Nov 2024

30 Two cylindrical conductors, X and Y, are made from the same material. The conductors have equal lengths, but Y has a smaller diameter than X. X and Y are connected in series to a cell. Which row compares the number of charge carriers per unit time passing through X and through Y and compares the average drift speed of the charge carriers in X and in Y? number of charge average drift speed carriers per unit time of charge carriers A Y greater than X Y greater than X B Y same as X Y same as X C Y greater than X Y same as X D Y same as X Y greater than X

1 marks

Answer: D

This question in 9702/12 Feb/March 2025

33 A metal electrical conductor has a resistance of 5.6 k. A potential difference (p.d.) of 9.0 V is applied across its ends. How many electrons pass a point in the conductor in one minute? A 6.0  1020 B 1.0  1019 C 6.0  1017 D 1.0  1016

1 marks

Answer: C

This question in 9702/12 Feb/March 2025

35 The diagram shows a junction in a circuit where three wires, P, Q and R, meet. The currents in P and Q are 1 A and 3 A respectively, in the directions shown. Q 3 A 1 A P R How much charge passes a given point in wire R in a time of 5 s? A 0.4 C B 2 C C 10 C D 20 C

1 marks

Answer: C

This question in 9702/12 Feb/March 2025

34 A resistor of resistance 200  is connected to a supply that has a p.d. of 4.00 V. How many electrons enter the resistor in 4.00 s? A 3.13  1016 B 1.25  1017 C 5.00  1017 D 1.25  1021

1 marks

Answer: C

This question in 9702/12 May/June 2025

2 What is a reasonable estimate of the current in an electric kettle that is in use? A 8 A B 8 mA C 8 A D 8 kA

1 marks

Answer: C

This question in 9702/13 May/June 2025

32 The current I in a metallic conductor of cross-sectional area A is given by I = Anve where e is the elementary charge and v is the mean drift velocity of the conduction electrons. What is represented by the letter n in the equation? A density of conduction electrons B number of conduction electrons per unit time C number of conduction electrons per unit volume D volume of conduction electrons

1 marks

Answer: C

This question in 9702/13 May/June 2025

33 What cannot be the charge on a charge carrier? A – 4.8  10–19 C B –3.2  10–19 C C –2.4  10–19 C D +3.2  10–19 C

1 marks

Answer: C

This question in 9702/13 May/June 2025

29 The resistance of a lamp is 10  and the potential difference across it is 6.0 V. How many electrons pass through the lamp in a time of 24 hours? A 5.2  104 B 9.0  1019 C 5.4  1021 D 3.2  1023

1 marks

Answer: D

This question in 9702/14 May/June 2025

32 What is a possible charge on a particle? A 6.40  10–20 C B 4.00  10–19 C C 1.12  10–18 C D 9.11  10–18 C

1 marks

Answer: C

This question in 9702/11 Oct/Nov 2025

32 What is a possible charge on a particle? A 6.40  10–20 C B 4.00  10–19 C C 1.12  10–18 C D 9.11  10–18 C

1 marks

Answer: C

This question in 9702/13 Oct/Nov 2025

33 The graphs show possible current–voltage (I–V ) characteristics for a filament lamp and for a semiconductor diode. I I I I 0 0 0 0 0 V 0 V 0 V 0 V P Q R S Which row identifies the I–V graphs for the lamp and for the diode? semiconductor filament lamp diode A P R B P S C Q R D Q S

1 marks

Answer: A

This question in 9702/13 Oct/Nov 2025

35 A wire carries a current of 5.6 A. What is the number of conduction electrons that pass a point on the wire in a time of 20 s? A 1.8  1018 B 2.2  1019 C 3.5  1019 D 7.0  1020

1 marks

Answer: D

This question in 9702/14 Oct/Nov 2025