Electricity and magnetism — IGCSE Physics (0972) questions by topic

Which row describes the magnetic properties of soft iron and steel? soft iron steel --- ----------- ------- A easy to demagnetise easy to demagnetise B easy to demagnetise hard to…

Two charged rods, X and Y, are brought, in turn, near to a negatively charged rod. X is attracted by the negatively charged rod, and Y is repelled. What are the charges on X and…

The table gives data for four different electrical devices. Which device develops the greatest power? device voltage current --- -------- --------- --------- A car headlight 12 V…

A mains-operated radio is a double-insulated appliance. Which statement is correct? A The radio does not need a neutral connection. B The radio must be earthed. C The radio…

Which statement describes a magnetic field? A It is a region where all objects experience a force. B It is a region where all electric charges experience a force. C It is a region…

A plastic rod is charged by friction. The plastic rod becomes positively charged. Which particles are transferred in this process? A atoms B electrons C protons D neutrons

A teacher makes a circuit using three 1.5 V cells and two 20 ohm resistors connected in series. (The circuit diagram shows the three cells in series and the two resistors in…

A student investigates the turning effect on a current-carrying coil placed in a magnetic field. The student changes the current in the coil and the number of turns on the coil.…

There is a current of 3.0 A in a conductor. The current is changed to 6.0 A in the opposite direction. Which effect does this have on the magnetic field around the conductor? A It…

A student has a bar magnet and two metal blocks. The student places the bar magnet next to end W and end X of metal block 1. The student then places the bar magnet next to end Y…

A glass rod is rubbed with a silk cloth. The glass rod becomes positively charged. Which statement explains how this happens? A Negative charges move from the glass rod to the…

Which statement describes what is happening when there is an electric current in a metal wire? A Electrons in the wire vibrate. B Electrons move along the wire. C Positive charges…

Which two electrical quantities have the same unit? A current and charge B electromotive force (e.m.f.) and potential difference (p.d.) C potential difference (p.d.) and current D…

A 10 V d.c. power supply is connected across a resistor. The current in the resistor is 0.050 A. What is the resistance of the resistor? A 0.0050 ohm B 0.50 ohm C 2.0 ohm D 200 ohm

A resistor and a thermistor are connected in a series circuit, as shown. The circuit has a cell, an ammeter (A) in the main loop, and a resistor in series with a thermistor; a…

In which circuit does the ammeter read 2.0 A? Each option shows a battery (two cells) connected in series with two resistors and an ammeter: A e.m.f. 12 V with two 6.0 ohm…

A 240 V mains-powered vacuum cleaner has a power output of 2700 W. Which fuse is suitable for use in the plug of the vacuum cleaner? A 3 A B 5 A C 10 A D 13 A

The transformer in a laptop power supply is used to change mains voltage from 240 V to 20 V. The transformer has 600 turns on the secondary coil. Which type of transformer is it…

The diagram shows a bracelet containing two magnets, one at J and one at K. The arrows represent the pattern and the direction of the magnetic field due to the magnets. The field…

Which row describes an electric field and its direction? description of electric field direction of electric field --- -------------------------------…

Copper wire is available in fixed lengths but in various diameters d. Each wire has a different resistance R. Which relationship between R and d is correct? A R is directly…

The diagram shows three 20 ohm resistors, R1, R2 and R3, and a switch S connected to a d.c. power supply. R1 and R2 are in parallel with each other; this parallel combination is…

The circuits shown all include a d.c. power supply, one diode and two light-emitting diodes (LEDs). Each circuit A-D has the supply at the top (positive terminal on the left,…

A wire connected to a resistor R is moved in a magnetic field between a N pole (left) and a S pole (right). A current is induced in the direction shown. Four candidate directions…

Which component is not found in an a.c. generator? A coil of wire B split-ring commutator C magnetic poles D slip rings

There is a current in a straight metal wire in the direction shown (the current flows vertically upwards, viewed from above). Which row describes the direction and the pattern of…

A simple transformer contains an iron core. What is the function of the iron core in the transformer? A to conduct current from the primary coil to the secondary coil B to enable…

A positively charged balloon is placed against a wall. The charge makes the balloon stick to the wall. Which statement explains this? A Positive charges on the balloon attract…

A metallic wire X has a resistance. What is the difference in resistance for a wire of the same material as X that is: - shorter than X but the same diameter - the same length as…

The diagram shows the circuit for a potential divider. A cell is connected across two resistors R1 and R2 in series. The output V1 is measured across R1 and the output V2 is…

Which electrical device is used to convert a.c. to d.c.? A diode B relay C thermistor D transformer

A cell is connected to a parallel combination of a 2.0 ohm resistor and a 4.0 ohm resistor. The current in the 4.0 ohm resistor is 1.0 A. The diagram shows a cell connected to two…

When there is an electric current in a long straight wire, a magnetic field is created around the wire. Which diagram shows the correct pattern and direction of magnetic field…

The primary voltage supplied to a transformer is 3.0 V. The secondary voltage is 5.0 V and the secondary current is 2.0 A. The transformer is 100% efficient. What is the primary…

Fig. 8.1 shows the circuit diagram for a 16 Ω resistor and an 8.0 Ω resistor connected to a 6.0 V battery. Calculate the combined resistance of the two resistors shown in Fig.…

Fig. 9.1 shows a router. The router emits Wi-Fi signals. The power input to the router circuit is 9.0 W. The potential difference across the router circuit is 12 V. Calculate the…

Fig. 8.1 shows a mains-powered electric fan heater fixed on a bathroom wall. Fig. 8.1 shows an electric fan heater mounted high on the wall with a pull cord hanging down from it.…

Fig. 9.1 shows two resistors connected in series. Fig. 9.1 shows a 20 Ω resistor and a 40 Ω resistor connected in series along a single wire. Calculate the combined resistance of…

Fig. 6.1 shows a person using a magnetic window cleaner. The part on the outside of the window is attracted to the inside part through the glass window. Each part of the window…

Fig. 7.1 shows a sketch of the current–voltage graph for an electrical component. The current is zero (or negligible) for negative voltages and for small positive voltages, then…

Fig. 8.1 shows a diagram of part of a simple a.c. generator. Identify components A and B in Fig. 8.1.

State what is meant by an electric field.

Fig. 8.1 shows a simplified diagram of an a.c. generator. A rectangular coil rotates between the poles of a magnet (N on the left, S on the right). Below the coil are two rings…

A student investigates a light-dependent resistor (LDR). The student assembles a series circuit consisting of a power supply, a switch, a 470 ohm resistor and an LDR. Fig. 2.1…

Which diagram shows the pattern and the direction of the magnetic field lines around a bar magnet? (Field lines go from N to S outside the magnet.) A, B, C, D show field line…

Which material is a good electrical conductor? A glass B copper C rubber D wood

What is an electric current and how is an ammeter positioned in a circuit to measure the current in a resistor? A current: a flow of charge; ammeter: in parallel with the resistor…

Which unit is used for the potential difference (p.d.) between two points in an electrical circuit? A ampere (A) B joule (J) C ohm (Ω) D volt (V)

The circuit in the diagram contains four switches, S1, S2, S3 and S4, controlling a heater. Which three switches must be closed for the heater to work? A S1, S2 and S3 B S1, S2…

The metal case of an electrical appliance is fitted with an earth connection. What is the purpose of this? A to complete the circuit supplying the appliance so that it works B to…

A student moves a magnet into a coil, as shown. The voltmeter measures the magnitude of the electromotive force (e.m.f.) induced in the coil. Which quantity does not affect the…

A student makes a small d.c. motor. The teacher supplies: battery, ammeter, voltmeter, coil of wire, magnets, resistor. The student may use other equipment too. Which equipment…

Small compasses are used to determine the direction of a magnetic field. Which diagram shows the direction that the compass needles point when placed near the N and S poles of a…

A metal bar is placed inside a current-carrying coil (diagram 1). There is a small current in the coil. The bar holds a few nails (diagram 2). When there is no current in the…

There is a current I in a resistor of resistance R. The potential difference (p.d.) across the resistor is V. Which equation gives the power P dissipated by the resistor? A P = IR…

A student tests the electrical conduction of four materials: aluminium, iron, plastic, silver. Which materials are good conductors of electricity? A aluminium, iron and silver B…

This question is about the potential difference (p.d.) across, and the current in, a variable resistor. The resistance of the variable resistor is increased. Which statement is…

Diagram 1 shows a resistor connected in a circuit. Diagram 2 shows an identical resistor connected in parallel with the first resistor. What is the combined resistance of the two…

Where must a fuse be connected in a mains electric circuit? A the earth wire only B the live wire only C the neutral wire only D the live wire and the earth wire

Which graph does not show the correct trend for the force F causing the turning effect on the coil in a d.c. motor? A F vs number of turns on the coil B F vs current C F vs…

Which row describes suitable materials for use in a temporary magnet and in a permanent magnet? A temporary: soft iron; permanent: soft iron B temporary: soft iron; permanent:…

A magnetic field is represented in the diagram by magnetic field lines. Points A, B, C, D lie at different places among the lines. At which point is the magnetic field strongest?…

A student determines the resistance of resistor R using a circuit including a voltmeter and an ammeter. (Voltmeter in parallel with R; ammeter in series.) Which circuit does she…

A diode and a resistor are connected across a variable d.c. supply. Terminal X is initially positive and at a maximum value. The p.d. across XY is adjusted so that it changes, as…

When a conductor in a complete circuit cuts across a magnetic field, a current is induced in the conductor. Which statement about the induced current is correct? A The induced…

The diagram shows a solenoid carrying an electric current, with points X, Y and Z (X and Z inside near the ends, Y inside the middle). Which row compares the strength of the…

A conducting wire is placed between the poles of a magnet (N on the left, S on the right). When an electric current in the wire is in the direction shown, the force on the wire…

Which types of electric current are in the primary coil and the secondary coil of a step-up transformer? A primary: a.c.; secondary: a.c. B primary: a.c.; secondary: d.c. C…

Which statement about the direction of a magnetic field at a point is correct? A It is the direction of the force on an N pole placed at that point. B It is the direction of the…

A student draws graphs of an a.c. supply and a d.c. supply, with axes labelled W (vertical) and the time axis, and the two supply curves X and Y. Which row shows the correct…

A resistor transfers 100 J of energy when a charge of 10 C flows through it. What is the potential difference across the resistor? A 0.10 V B 10 V C 10 W D 1000 W

Wire X and wire Y are made from the same metal. The table gives information about the two wires. length / m cross-sectional area / mm² resistance / Ω --- --- --- --- wire X 1.0…

The diagram shows two resistors used as a potential divider: a 5.0 kΩ resistor in series with resistor R across a 3.0 V supply, with a voltmeter across R. The reading on the…

Two electrical appliances are connected to the mains supply. The cable connected to one appliance includes an earth wire; the cable connected to the second appliance does not need…

The diagram shows a simple a.c. generator. A magnet rotates around a fixed coil wound on a fixed iron core. The e.m.f. output is a sine wave. The magnet is shown in three…

A 24 V power supply and a 100% efficient transformer are used to light a 6.0 V, 12 W lamp. What is the current in the power supply? A 0.50 A B 2.0 A C 3.0 A D 8.0 A

Fig. 8.1 shows an arrangement for making an electromagnet (a solenoid and a core, connected to a 12 V battery via a variable resistor and an ammeter). The electromagnet is a…

Fig. 9.1 shows the power cable for connecting a desktop computer to the mains electricity circuit, containing three wires. State the name of each of the three wires inside the…

A battery, a lamp L, a fixed resistor R and a switch S are connected as shown in Fig. 7.1 (6.0 V battery; R in series with the parallel combination of L and the branch containing…

The battery in a laptop computer is connected to a battery charger for 20 minutes. The potential difference (p.d.) across the battery is 14 V and the current in the battery is 1.8…

Fig. 9.1 shows an electricity cable that has a fault: the plastic insulation is damaged, exposing the copper wire. The cable is used for supplying electricity at a high voltage.…

Fig. 6.1 shows an isolated metal sphere suspended by an insulating thread from the ceiling. The sphere is negatively charged. The charge on the sphere produces an electric field…

The electromotive force (e.m.f.) of a battery is 7.5 V. Define the term electromotive force.

Fig. 7.1 shows three bars of steel, A, B and C. [Diagram: three identical rectangular steel bars labelled A, B and C, arranged vertically one above the other.] A student is given…

Fig. 8.1 shows a circuit. The circuit is designed to switch on a night light when the surroundings are dark. The circuit contains a light-dependent resistor (LDR) in parallel with…

In this experiment, you will investigate the resistance of a wire. Fig. 2.1 shows a circuit with a resistance wire BC, an ammeter, a voltmeter, a switch, and a sliding contact S…

A student investigates the resistance of a wire. Fig. 2.1 shows the circuit used with a resistance wire BC, sliding contact S, ammeter, and voltmeter. The student measures the…

A student investigates the resistance of a diode. Fig. 2.1 shows the circuit used. Fig. 2.2 shows the meters when the variable resistor is set so that the current in the circuit…

A bar magnet (with poles X and Y) is next to a steel bar. The field lines go from X outward and converge towards Y. The steel bar is to the right of Y. What are the correct poles…

Which row about electrical conduction in metals is correct? statement 1 statement 2 --- --- --- A It is the movement of free electrons. Electric charge is a flow of current. B It…

The diagram shows three wires, P, Q and R, all made from the same metal. P has length 2 cm and cross-section 0.8 cm², Q has length 4 cm and cross-section 0.8 cm², R has length 2…

A 60 W lamp operates at normal brightness for 2.0 minutes. How much energy is transferred by the lamp? A 0.50 J B 30 J C 120 J D 7200 J

What is a thermistor? A a container to keep a hot liquid warm B a circuit to control room temperature C a temperature-dependent resistor D a heater for a room

The diagram shows a circuit containing two identical resistors connected to a battery. The resistors are connected in parallel, with current measured at X (before the parallel…

The mains voltage is 120 V. Which fuse should be fitted to an electric kettle with a power of 1.5 kW? A 3 A B 5 A C 10 A D 13 A

The diagrams show three arrangements: X = strong magnet moving slowly into a coil, Y = weak magnet moving slowly into a coil, Z = strong magnet moving quickly into a coil. Which…

The diagrams show a current-carrying wire with an arrow in the direction of the current. Four diagrams A–D show different magnetic field configurations. Which diagram shows the…

What are the best materials to use for the construction of a transformer? A copper for the core and steel for the coils wound around it B copper for the core and copper for the…

The diagram shows part of the magnetic field around a strong magnet. Positions A, B, C, D are marked at various distances from the magnet's end. In which position does a magnetic…

There is a current of 0.60 A in a closed circuit. How much charge passes a point in the circuit in 2.5 min? A 0.24 C B 1.5 C C 90 C D 5400 C

Which two physical quantities have the unit J/C? A charge and energy B charge and potential difference (p.d.) C electromotive force (e.m.f.) and p.d. D e.m.f. and charge

A copper wire is placed in an electrical circuit and its resistance is measured. The wire is then replaced with a second copper wire with twice the length and a quarter of the…

Which circuit contains a diode connected in series with a fixed resistor? Four circuit diagrams A–D show different component combinations. A LDR and resistor in series B variable…

In the circuit shown, resistor X has twice the resistance of resistor Y. They are connected in parallel. Which statement about the circuit is correct? A The current in the cell is…

A 4 Ω resistor and an 8 Ω resistor are connected in series with a power supply. A voltmeter connected across the 8 Ω resistor reads 36 V. What is the voltmeter reading when it is…

A metal rod, XY, is placed in a magnetic field so that it is perpendicular to the field. The field lines point to the right. The rod is vertical (X at top, Y at bottom). In which…

The diagram shows a basic electric motor with features labelled X, Y and Z. X is at the top of the coil, Y and Z are at the base where the commutator and brushes are. What are the…

Two transformers, P and Q, each have 2000 turns on their primary coils and 1000 turns on their secondary coils. Both transformers are 100% efficient. The secondary of transformer…

A student tests various materials to determine whether they are electrical conductors or insulators. The student uses the circuit shown in Fig. 9.1, which contains a 6 V battery,…

In an experiment, a student uses an electrical heater connected to a power supply. The current in the electrical heater is 2.2 A. The voltage (p.d.) across the heater is 12 V.…

A potential divider is made by connecting a light-dependent resistor (LDR) and a thermistor in series. The voltmeter measures the potential difference (p.d.) across the LDR.…

A solid bar is inside a copper solenoid. The copper solenoid is connected in series with a battery and a variable resistor. The device shown is an electromagnet. Suggest a…

A student investigates the current required to melt different fuse wires. Fig. 4.1 shows part of the circuit the student uses. The following equipment is also available: - fuse…

An unmagnetised piece of soft iron is placed close to a strong permanent magnet, as shown. The magnet's poles, from left, are S then N, with end N facing the soft iron. End X is…

A plastic rod is rubbed with a cloth. The rod and the cloth both become charged as electrons move between them. The rod becomes negatively charged. Which diagram shows how the rod…

Which particles move to cause a current in a copper wire? A copper atoms B electrons from the copper atoms C protons from the copper nuclei D neutrons from the copper nuclei

Four students draw a circuit diagram of the apparatus used to measure the resistance of resistor R. The correct circuit has a voltmeter (V) connected in parallel across R and an…

The battery on a bicycle is connected in parallel to its lamp and bell. The circuit includes two switches, S1 and S2. The cyclist closes S1 to light the lamp. She then also closes…

Which symbol represents an electric heater? A, B, C, D are four circuit symbols; the electric heater is represented by a rectangle (resistor) symbol. The answer is the standard…

A student connects the circuit shown. There is a bell, a lamp, and four switches labelled 1, 2, 3 and 4. Which switches must be closed for the bell to ring without lighting the…

A double-insulated electrical appliance must be connected safely to the electricity supply. Which statement is correct? A It must be connected with a fuse and an earth wire. B It…

A simple electric generator induces an electromotive force (e.m.f.). Which modification would increase the induced e.m.f.? A Increase the number of turns in the coil of the…

The diagram shows a vertical wire carrying a current I placed between the poles of a magnet (N pole on the left, S pole on the right). The current I flows upward. What is the…

What is an advantage of transmitting electricity at a high voltage? A It is faster. B It is safer. C Less energy is wasted. D Less equipment is needed.

The magnetic field of a bar magnet can be represented by magnetic field lines. Which diagram shows two magnetic field lines correctly? (Field lines run from N to S outside the…

A plastic rod is rubbed with a dry cloth. The rod becomes positively charged. Why has the rod become positively charged? A It has gained electrons. B It has gained neutrons. C It…

Which statement about electric current in a conductor is correct? A In a d.c. circuit, the electric current gradually decreases along the conductor. B In a d.c. circuit, the free…

Which circuit can be used to measure the resistance of a resistor? (A correct circuit has the voltmeter V in parallel with the resistor and the ammeter A in series.) A, B, C, D…

A lamp rated 12 V, 2.0 A is switched on for 60 s. How much energy is transferred? A 0.40 J B 10 J C 360 J D 1400 J

The circuit diagram shows a battery connected to two resistors (2.0 Ω and 1.0 Ω). Four labelled ammeters A, B, C, D are connected into the circuit. Which ammeter shows the largest…

Two lamps are connected in parallel, with switches S1, S2 and S3 in the circuit. Which switches must be closed so that both lamps light? A S1 and S2 only B S1 and S3 only C S2 and…

Which statement about electrical safety is correct? A If a device is double insulated, it does not need a fuse. B A device that has a normal operating current of 3.0 A must be…

A student investigates the output voltage induced across a coil of wire by a bar magnet. When will the induced voltage have the greatest value? A The student slowly moves the bar…

In which device is the magnetic effect of a current not used? A electromagnet B loudspeaker C potential divider D relay

The diagram represents the transmission of electricity from a power station to homes that are many kilometres away. Two transformers are labelled X (near the power station) and Y…

An unmagnetised piece of soft iron is placed close to a strong permanent magnet, as shown (magnet poles S then N from the left, N facing the soft iron). End X of the soft iron is…

A plastic rod is rubbed with a cloth. The rod and the cloth both become charged as electrons move between them. The rod becomes negatively charged. Which diagram shows how the rod…

A wire has a uniform circular cross-sectional area. Which statement is correct? A The resistance of the wire is directly proportional to its cross-sectional area and inversely…

The diagram shows the current–voltage graph for a metal wire. The graph curves so that the gradient decreases as voltage increases. What can be deduced from the graph? A As…

A battery is connected to a circuit. It is switched on for 1.0 minute. During that time, there is a current of 0.40 A in the circuit and the battery supplies a total of 48 J of…

The circuit diagram shows two identical lamps connected in parallel to a cell. Three ammeters, X, Y and Z, are also connected in the circuit. X is in the main line; Y and Z are in…

A student connects the circuit shown, containing a bell, a lamp and four switches numbered 1, 2, 3 and 4. Which switches must be closed for the bell to ring without lighting the…

The diagram shows an a.c. generator with a coil rotating between magnet poles N and S, and terminals X and Y. The graph shows the potential difference between points X and Y…

An electron moves into a uniform magnetic field. The arrow shows the initial direction of motion of the electron. The direction of the magnetic field is into the plane of the…

Which statement about a transformer is correct? A There is an alternating current in the iron core from the primary coil to the secondary coil. B An alternating current in the…

The magnetic field of a bar magnet can be represented by magnetic field lines. Which diagram shows two magnetic field lines correctly? (Field lines run from N to S outside the…

A plastic rod is rubbed with a dry cloth. The rod becomes positively charged. Why has the rod become positively charged? A It has gained electrons. B It has gained neutrons. C It…

Which statement about electric current in a conductor is correct? A In a d.c. circuit, the electric current gradually decreases along the conductor. B In a d.c. circuit, the free…

A piece of metal wire X with a uniform diameter has resistance R. A second piece of wire Y is made of the same metal and has a uniform diameter. Y has double the cross-sectional…

An electric fire is connected to a 240 V supply and transfers energy at a rate of 1.0 kW. How much charge passes through the fire in 1.0 h? A 42 C B 250 C C 1.5 × 10⁴ C D 2.4 ×…

Two lamps are connected in parallel, with switches S1, S2 and S3 in the circuit. Which switches must be closed so that both lamps light? A S1 and S2 only B S1 and S3 only C S2 and…

The diagram shows a circuit that switches on a lamp when there is a change in the environment. Which change in the environment causes the lamp to be switched on? A a decrease in…

A step-down transformer is 100% efficient. It has an input voltage of 240 V a.c. and an output voltage of 60 V a.c. The current in the primary coil is 0.50 A. What is the current…

The diagram shows the pattern of the magnetic field due to the current I in a straight wire. Points P and Q are at different distances from the wire (Q closer than P), and X and Y…

In which device is the magnetic effect of a current not used? A electromagnet B loudspeaker C potential divider D relay

Fig. 8.1 shows the magnetic field pattern around two permanent magnets. The magnets are repelling each other. On Fig. 8.1, label both the poles on each magnet.

Fig. 9.1 shows a series circuit. Two of the components in the circuit are labelled (a power supply and a lamp). State the name of two other components in the circuit.

Fig. 10.1 shows an arrangement used to demonstrate electromagnetic induction. A permanent magnet (S–N) moves towards a coil of wire connected to a sensitive voltmeter. When the…

A student uses a permanent magnet to lift some unmagnetised nails. Some of the nails are made of iron and some are made of steel. Fig. 7.1 shows the magnet lifting chains of…

A student uses the circuit in Fig. 8.1 to measure the resistance of the heater in the circuit. The symbols for the meters in Fig. 8.1 are incomplete (empty circles). Complete the…

A student has a desktop computer that connects to the 240 V a.c. mains electrical supply. The desktop computer has an on-off switch in one of the wires that connect it to the…

Fig. 7.1 shows a circuit that contains a battery, a switch, a voltmeter and three 40 Ω resistors, R1, R2 and R3. The switch is open and resistors R1 and R2 form a potential…

The electricity supplied to a town is transmitted using a high-voltage cable. A transformer in the town has a soft-iron core. Explain the principle of operation of a simple…

State what is meant by a magnetic field.

A student investigates the change in resistance of a lamp filament when the current in the lamp is increased. The following apparatus is available: a power supply, a low-voltage…

A student investigates the change in resistance of a lamp filament when the current in the lamp is increased. The following apparatus is available: a power supply, a low-voltage…

A student investigates the change in current in a conducting liquid as the distance between two electrodes is changed. The circuit is shown in Fig. 4.1 (a power source, an ammeter…

Which metal could be used for a permanent magnet and which metal could be used for the core of an electromagnet? A permanent magnet: iron; core: copper B permanent magnet: iron;…

Object 1 is given a negative charge and placed on a balance. Object 2, which is also charged, is brought close to object 1 and the reading on the balance changes from 93.5 g to…

Which statement about a voltmeter is correct? A It has a scale which is marked in amperes (A). B It must be connected in series in a circuit. C It measures potential difference…

How does the resistance of a metallic wire change: • as its length increases • as its cross-sectional area decreases? A length increases: decreases; area decreases: decreases B…

A plastic rod is rubbed with a cloth. The rod becomes positively charged because of the movement of charged particles. Which row gives the name of these charged particles and the…

Two 2.0 Ω resistors are connected in parallel. What is the combined resistance of the resistors? A less than 2.0 Ω B exactly 2.0 Ω C more than 2.0 Ω, but less than 4.0 Ω D exactly…

An electric heater is plugged into the mains supply using a fused plug. The current in the heater is 10 A. The cable attached to the heater is rated at 15 A. The fuses available…

A teacher sets up the equipment for three demonstrations, P, Q and R. • In demonstration P, a magnet is moved to the right relative to a coil connected to a voltmeter. • In…

A metal rod PQ rests on two horizontal metal wires attached to a battery. The rod lies between the poles of a magnet (N at top, S at bottom). When the switch is closed, the rod…

A transformer in a computer is used to transform the mains voltage of 240 V to 12 V. The number of turns on the secondary coil is 2000. Which statement about the transformer is…

Which metal could be used for a permanent magnet and which metal could be used for the core of an electromagnet? A permanent magnet: iron; core: copper B permanent magnet: iron;…

Which statement describes the direction of an electric field at a point? A the direction of the force on a negative charge B the direction of the force on an N pole C the…

Which statement about a voltmeter is correct? A It has a scale which is marked in amperes (A). B It must be connected in series in a circuit. C It measures potential difference…

A wire has a resistance of 8.0 Ω. A second wire of the same material has twice the length and twice the cross-sectional area. What is the resistance of the second wire? A 4.0 Ω B…

A plastic rod is rubbed with a cloth. The rod becomes positively charged because of the movement of charged particles. Which row gives the name of these charged particles and the…

An alternating (a.c.) supply is connected to a diode and a resistor in series. Which graph shows how the potential difference V across the resistor varies with time t? (A diode…

The diagram shows a circuit used to switch on a heater when the temperature drops below a certain value. Components are to be connected at positions X and Y. Which row shows the…

A current in a solenoid produces a uniform magnetic field inside the solenoid. The magnetic field direction is due east. Which changes will produce a stronger magnetic field with…

A metal rod PQ rests on two horizontal metal wires attached to a battery. The rod lies between the poles of a magnet (N at top, S at bottom). When the switch is closed, the rod…

A transformer in a computer is used to transform the mains voltage of 240 V to 12 V. The number of turns on the secondary coil is 2000. Which statement about the transformer is…

Fig. 6.1 shows four wind turbines. Describe how a wind turbine generates electrical power.

Fig. 8.1 shows a solenoid (long coil of wire) connected in a circuit. When the switch is closed, there is a large current in the circuit. Describe an experiment to identify the…

A student investigates an electric circuit. Fig. 9.1 shows the student's circuit (a 6.0 V battery, a variable resistor, an ammeter A and a heater). Describe the purpose of the…

A plastic rod is uncharged. When the rod is rubbed with a woollen cloth, the rod becomes negatively charged. Explain, in terms of particles, why the rod becomes negatively charged.

A cylinder is made of modelling clay (an electrical conductor). It is connected into a circuit (Fig. 8.2) with a battery of e.m.f. 9.0 V and a resistor P. The resistance of P is…

A student investigates the resistance of a resistance wire. Fig. 2.1 shows the circuit (battery, switch, ammeter A, voltmeter V across length l of the resistance wire from B to…