Physics 9702 · AS & A Level
Electric potential
85 practice questions on Electric potential, with worked solutions and instant marking.
With a labelled diagram, describe the arrangement of a metal-wire strain gauge.
Feb/March 2017
State the meaning of electric potential at a point.
Feb/March 2018
In Fig. 7.1, sketch the temperature characteristic of a negative temperature coefficient (n.t.c.) thermistor. Put the quantity and unit on each axis.
Feb/March 2020
State one likeness between the gravitational field lines around a point mass and the electric field lines around a point charge.
Feb/March 2021
State what an electric field line shows.
Feb/March 2022
What does the term potential energy of a body mean?
May/June 2010
Fig. 9.1 shows the circuit diagram of an amplifier circuit that includes an operational amplifier (op-amp).
May/June 2010
Define electric potential at a point in words.
May/June 2011
An operational amplifier (op-amp) can act as a comparator. State the purpose of a comparator.
May/June 2011
Section B. Answer every question in the spaces provided.
May/June 2011
Section B. Answer every question in the spaces provided.
May/June 2011
A point mass with charge is placed in a vacuum. A proton moves directly towards the mass, as shown in Fig. 4.1. When the distance between the mass and the proton is $r$, the electric potential energy of the system is $U_p$. Fig. 4.2 shows how the potential energy $U_p$ varies with $r$.
May/June 2012
Define electric potential at a point in terms of work done.
May/June 2013
Suggest one electrical sensing device for each situation that could be used to track changes in
May/June 2013
A sensing device tracks the amount of fuel in a car’s fuel tank. It produces a voltage output, which is measured with a voltmeter. Fig. 9.1 shows how the voltmeter reading changes as the fuel volume in the tank changes.
May/June 2013
Define electric potential at a point in terms of the work needed to bring a unit positive test charge from infinity to that point.
May/June 2013
Suggest one electrical sensing device for each case that may be used to monitor changes in
May/June 2013
Fig. 11.1 shows a circuit that includes an ideal operational amplifier (op-amp).
May/June 2014
A single isolated metal sphere of radius $r$ carries a positive charge. Let $x$ represent the distance from the sphere’s centre.
May/June 2014
The circuit diagram in Fig. 11.1 contains an ideal operational amplifier (op-amp).
May/June 2014
An isolated solid metal sphere of radius $r$ is charged positively. Let the distance from its centre be $x$.
May/June 2014
An operational amplifier (op-amp) is employed in the comparator circuit shown in Fig. 10.1.
May/June 2015
A charged metal sphere is placed in isolation in space. The electric potential $V$ is measured at a range of distances $x$ from the sphere’s centre. Figure 5.1 shows how the potential $V$ changes with distance $x$.
May/June 2015
Define electric potential at a point in a field.
May/June 2015
A strain gauge is being used to track the strain in a beam, and it forms part of the potential divider circuit shown in Fig. 9.1. When no strain is applied, the strain gauge has a resistance of $120.0\,\Omega$. If the strain becomes $\varepsilon$, the resistance rises to $121.5\,\Omega$.
May/June 2015
In the comparator circuit shown in Fig. 10.1, an operational amplifier (op-amp) is employed.
May/June 2015
A charged metal sphere is placed alone in space. The electric potential $V$ is measured at a range of distances $x$ from the centre of the sphere. Fig. 5.1 shows how the potential $V$ changes with distance $x$.
May/June 2015
A solid metal sphere with radius $R$ is isolated in space. The sphere carries a positive charge so that the electric potential at its surface is $V_S$. The electric field strength at the surface is $E_S$.
May/June 2016
The inverting-amplifier circuit using an ideal operational amplifier (op-amp) is shown in Fig. 8.1.
May/June 2016
A solid metal sphere with radius $R$ is isolated in space. It carries a positive charge such that the electric potential at its surface is $V_S$. At the surface, the electric field strength is $E_S$.
May/June 2016
A student builds a circuit that includes an operational amplifier (op-amp), as shown in Fig. 8.1.
May/June 2017
Negative feedback is commonly applied in amplifiers that use an operational amplifier (op-amp).
May/June 2018
Negative feedback is frequently used in amplifiers that contain an operational amplifier (op-amp).
May/June 2018
Figure 7.1 shows the circuit arrangement of an inverting amplifier using an ideal operational amplifier (op-amp).
May/June 2019
State the meaning of electric potential at a point.
May/June 2019
Use band theory to explain why the resistance of an intrinsic semiconductor falls as temperature increases.
May/June 2019
Fig. 7.1 shows the circuit arrangement for an inverting amplifier that uses an ideal operational amplifier (op-amp).
May/June 2019
Fig. 8.1 plots how the resistance of a thermistor changes as temperature changes. A student then places the thermistor together with an ideal operational amplifier (op-amp) in the circuit shown in Fig. 8.2.
May/June 2021
The way the thermistor’s resistance changes with temperature is shown in Fig. 8.1. A student puts the thermistor and an ideal operational amplifier (op-amp) into the circuit in Fig. 8.2.
May/June 2021
Define the term gravitational field.
May/June 2023
Define the electric potential at a point.
May/June 2024
What is meant by electric potential at a point?
May/June 2025
Two small charged metal spheres A and B are placed in a vacuum. Their centres are separated by $12.0\,\text{cm}$, as shown in Fig. 4.1. It may be assumed that the charge on each sphere acts as a point charge at the centre of the sphere. Point P is a movable point on the line joining the centres of the spheres, at a distance $x$ from the centre of sphere A. Fig. 4.2 shows how the electric field strength $E$ at point P varies with distance $x$.
Oct/Nov 2011
In a vacuum, two small charged metal spheres A and B are placed as shown in Fig. 4.1. The separation between their centres is $12.0\,\text{cm}$. The charge on each sphere may be treated as a point charge at the sphere’s centre. Point P is a movable point on the straight line joining the centres of the spheres, and its distance from the centre of sphere A is $x$. Fig. 4.2 shows how the electric field strength $E$ at P varies with distance $x$.
Oct/Nov 2011
A light-dependent resistor (LDR) has a resistance of about $500\ \Omega$ in daylight. Give an approximate resistance for the LDR in darkness.
Oct/Nov 2011
An operational amplifier (op-amp) can form part of the processing section in an electronic sensor.
Oct/Nov 2012
An operational amplifier (op-amp) can form part of the processing section in an electronic sensor.
Oct/Nov 2012
Fig. 9.1 can be used to represent an electronic sensor with a block diagram.
Oct/Nov 2013
An electronic sensor can be shown using the block diagram in Fig. 9.1.
Oct/Nov 2013
Define electric potential at a point in words.
Oct/Nov 2013
Write your answers in the spaces provided for each question.
Oct/Nov 2014
Define electric potential at a point in an electric field.
Oct/Nov 2014
Part B
Oct/Nov 2014
Define electric potential at a point in an electric field.
Oct/Nov 2014
The block diagram in Fig. 10.1 can be used to represent an electronic sensor.
Oct/Nov 2014
Define electric potential at a point in space.
Oct/Nov 2014
A battery with e.m.f. $6.0\ \text{V}$ and negligible internal resistance is linked to three resistors, each having resistance $2.0\ \text{k}\Omega$, together with a thermistor, as illustrated in Fig. 9.1. The thermistor’s resistance is $2.8\ \text{k}\Omega$ at $10\,^{\circ}\text{C}$ and $1.8\ \text{k}\Omega$ at $20\,^{\circ}\text{C}$.
Oct/Nov 2015
A battery with e.m.f. $6.0\ \text{V}$ and negligible internal resistance is joined to three resistors, each of resistance $2.0\ \text{k}\Omega$, together with a thermistor, as shown in Fig. 9.1. The thermistor has a resistance of $2.8\ \text{k}\Omega$ at $10^{\circ}\text{C}$ and a resistance of $1.8\ \text{k}\Omega$ at $20^{\circ}\text{C}$.
Oct/Nov 2015
A solid metal sphere carrying positive charge is isolated in space. The electric field strength $E$ is recorded at various distances $x$ from the sphere’s centre. Fig. 5.1 shows how the field strength $E$ changes with $x$.
Oct/Nov 2015
There are two small solid metal spheres A and B, each with the same radius, in a vacuum. Their centres are separated by 15\,\text{cm}. Sphere A carries a charge of +3.0\,\text{pC} and sphere B carries a charge of +12\,\text{pC}. Fig. 5.1 shows the layout. Point P is on the straight line joining the sphere centres and is 5.0\,\text{cm} from the centre of sphere A.
Oct/Nov 2016
The slew rate of an ideal operational amplifier (op-amp) is infinite. State what is meant by infinite slew rate.
Oct/Nov 2016
Two solid metal spheres A and B, each with radius $1.5\,\text{cm}$, are placed in a vacuum. The centres of the spheres are $20.0\,\text{cm}$ apart, as shown in Fig. 6.1. Both spheres have positive charge. Point P is located on the straight line joining the centres of the two spheres, at a distance $x$ from the centre of sphere A. Fig. 6.2 shows how the electric field strength $E$ at point P varies with distance $x$.
Oct/Nov 2016
Fig. 8.1 shows a circuit containing an ideal operational amplifier (op-amp). The op-amp is supplied with $+9\,\text{V} / -9\,\text{V}$. A voltmeter with range $0 - 5.0\,\text{V}$ is used to measure the amplifier output. A switch allows the inverting input of the op-amp to be linked to either resistor $R_A$ or resistor $R_B$.
Oct/Nov 2016
Two tiny solid metal spheres A and B, each with the same radius, are in a vacuum. Their centres are 15\ \text{cm} apart. Sphere A carries a charge of +3.0\ \text{pC} and sphere B carries +12\ \text{pC}. Fig. 5.1 shows the arrangement. Point P lies on the line joining the centres of the spheres, at a distance of 5.0\ \text{cm} from the centre of sphere A.
Oct/Nov 2016
Fig. 7.1 shows the amplifier circuit that uses an ideal operational amplifier (op-amp).
Oct/Nov 2017
For any location outside a spherical conductor, the charge on the sphere can be treated as though it were a point charge at the centre. Use electric field lines to explain why.
Oct/Nov 2017
Define the term electric potential at a point.
Oct/Nov 2018
In a vacuum, two similar solid metal spheres A and B, each with radius $R$, have their centres separated by $D$, as shown in Fig. 6.1. Sphere A carries charge $+Q$ and sphere B carries charge $+q$, with $+Q$ greater than $+q$. A movable point $P$ lies on the straight line joining the centres of the two spheres. Point $P$ is at a distance $x$ from the centre of sphere A.
Oct/Nov 2018
Figure 7.1 shows a circuit built around an ideal operational amplifier (op-amp). Figure 7.2 gives how the thermistor resistance $R_T$ varies with temperature $\theta$.
Oct/Nov 2018
Define electric potential at a point in space.
Oct/Nov 2018
An ideal operational amplifier (op-amp) is regarded as having infinite bandwidth and zero output impedance.
Oct/Nov 2019
Define what electric potential at a point means.
Oct/Nov 2019
Define electric potential at a point in terms of the work done per unit charge.
Oct/Nov 2020
An ideal operational amplifier (op-amp) will be used within a comparator circuit. A section of the comparator is illustrated in Fig. 7.1. To finish the circuit, there are three resistors, each with resistance $1000\,\Omega$, together with a negative temperature coefficient thermistor. The arrangement must be set up so that the output $V_{\text{OUT}}$ is $-5.0\,\text{V}$ at low temperatures and $+5.0\,\text{V}$ at higher temperatures.
Oct/Nov 2020
Define what electric potential at a point means.
Oct/Nov 2020
An ideal operational amplifier (op-amp) is to be used as a comparator circuit. Fig. 7.1 shows part of the comparator circuit. To finish the circuit, three resistors, each with resistance $1000\,\Omega$, and a negative temperature coefficient thermistor are available. The circuit should be arranged so that, at low temperatures, the output $V_{\text{OUT}}$ is $-5.0\,\text{V}$, whereas at higher temperatures, the output $V_{\text{OUT}}$ is $+5.0\,\text{V}$.
Oct/Nov 2020
Define electric potential in terms of work done per unit charge.
Oct/Nov 2021
Define the electric potential at a point.
Oct/Nov 2022
Define electric potential at a point in an electric field.
Oct/Nov 2023
Define electric potential at a point in terms of the work done per unit charge.
Oct/Nov 2023
State the connection between electric field and electric potential.
Oct/Nov 2024
State the connection between electric field and electric potential.
Oct/Nov 2024
A hydrogen atom can be treated as containing a proton and an electron with a separation of $120\,\text{pm}$, as illustrated in Fig. 5.1. The two particles may be modelled as point charges. Point P is on the straight line joining the electron and the proton, and its distance from the proton is variable, equal to $x$.
Oct/Nov 2025
A hydrogen atom can be taken to comprise a proton and an electron with a separation of $120\,\text{pm}$, as illustrated in Fig. 5.1. Treat both particles as point charges. Point P is located on the straight line between the electron and the proton, at a variable distance $x$ from the proton.
Oct/Nov 2025
A positively charged isolated metal sphere has radius $R$, as in Fig. 5.1. The line XY passes through the sphere’s centre. Point P is on line XY and is a variable displacement $x$ from the centre of the sphere. Point Q is fixed and is not on line XY. The electric field strength at the surface of the sphere is $E_0$.
Oct/Nov 2025