Danho
ZIMSEC O Level · 4023/2 · N2025

Physics Paper 2 November 2025

Questions
78
Total marks
120
Time allowed
120 min
Syllabus code
4023/2

Sit this paper online

Questions
78
Pass mark
47
Sit this paper

Answer every question in the printed order, get marked at the end, then see the answers.

The questions

Question 101

[1 marks]Physical quantity, base quantities, and deducing the base unit of power
A physical quantity is best described as a quantity that...
  1. Aexists only as a unit, without any numerical value.
  2. Bcan be measured, and consists of a numerical magnitude together with a unit.
  3. Ccannot be measured directly or indirectly, since it exists only as an idea with no way to assign it a numerical value.
  4. Dconsists only of a number, with no unit needed.

Question 102

[1 marks]Physical quantity, base quantities, and deducing the base unit of power
Name the base (fundamental) quantity used to measure how hot or cold an object is.

Answer this when you sit the paper.

Question 103

[1 marks]Physical quantity, base quantities, and deducing the base unit of power
Which of the following is a base (fundamental) quantity, rather than a quantity derived from combining others?
  1. AMass
  2. BForce
  3. CMomentum
  4. DSpeed

Question 104

[2 marks]Physical quantity, base quantities, and deducing the base unit of power
Power is defined as work done per unit time, and work done is force multiplied by distance. Deduce the base unit of power, in terms of kg, m and s.

Answer this when you sit the paper.

Question 201

[1 marks]Free-body force diagram of a pulled block, and a parachutist falling to terminal velocity
A wooden block rests on a rough horizontal surface. It is pulled to the right by a horizontal force P, and a normal reaction R acts vertically upward on it. Which force, present in reality but not drawn in the diagram, opposes the block's motion?
  1. AFriction
  2. BUpthrust
  3. CWeight
  4. DTension

Question 202

[1 marks]Free-body force diagram of a pulled block, and a parachutist falling to terminal velocity
A wooden block is pulled across a rough horizontal surface. Give one practical way of minimizing the friction force acting on it.

Answer this when you sit the paper.

Question 203

[2 marks]Free-body force diagram of a pulled block, and a parachutist falling to terminal velocity
A parachutist and parachute of total mass 80 kg fall from rest, vertically downwards. At the very instant they start to fall from rest, state the values of P (the air resistance on the canopy) and Q (the weight), taking g = 10 N/kg.

Answer this when you sit the paper.

Question 204

[1 marks]Free-body force diagram of a pulled block, and a parachutist falling to terminal velocity
A parachutist of weight 800 N eventually falls at a constant (uniform, terminal) velocity. State the value of P, the air resistance acting on the parachute, at this constant velocity.

Answer this when you sit the paper.

Question 301

[1 marks]Roles of a carburettor and spark plug, and comparing engine efficiency from exhaust gas composition
State one role of a carburettor in a petrol engine.

Answer this when you sit the paper.

Question 302

[1 marks]Roles of a carburettor and spark plug, and comparing engine efficiency from exhaust gas composition
State the function of a spark plug in a petrol engine.

Answer this when you sit the paper.

Question 303

[1 marks]Roles of a carburettor and spark plug, and comparing engine efficiency from exhaust gas composition
Engine A's exhaust gas is 65% water, 15% carbon monoxide and 20% carbon dioxide. Engine B's exhaust gas is 65% water, 5% carbon monoxide and 30% carbon dioxide. State which engine, A or B, is the more efficient.

Answer this when you sit the paper.

Question 304

[2 marks]Roles of a carburettor and spark plug, and comparing engine efficiency from exhaust gas composition
Engine A's exhaust gas is 65% water, 15% carbon monoxide and 20% carbon dioxide; engine B's is 65% water, 5% carbon monoxide and 30% carbon dioxide. Engine B is judged more efficient than engine A mainly because...
  1. Aengine A's higher carbon monoxide reading shows it burns its fuel faster, which makes it the more efficient engine.
  2. Bengine B produces less carbon monoxide and more carbon dioxide, showing more complete combustion of its fuel.
  3. Cengine B produces the same percentage of water as engine A, which always indicates better efficiency on its own.
  4. Dengine B produces more carbon monoxide, which always signals a hotter and therefore more efficient burn.

Question 401

[1 marks]How sound travels through air, and why an explosion on the moon cannot be heard
State the type of wave, in terms of how the particles vibrate relative to the wave's direction of travel, that sound is when it moves through air.

Answer this when you sit the paper.

Question 402

[2 marks]How sound travels through air, and why an explosion on the moon cannot be heard
As sound travels through air from a vibrating source to a listener, which statement best describes what actually happens to the air particles themselves?
  1. AEach particle physically travels all the way from the source to the listener, carrying the sound's energy with it as it moves through the air.
  2. BThe particles do not move at all; only the air pressure changes instantly everywhere at once.
  3. CThe particles move only in a direction perpendicular to the sound's direction of travel.
  4. DThe particles vibrate back and forth about a fixed position, passing the vibration on to neighbouring particles as a moving series of compressions and rarefactions.

Question 403

[1 marks]How sound travels through air, and why an explosion on the moon cannot be heard
State the property missing from the moon's surroundings that prevents sound from an explosion there from being heard.

Answer this when you sit the paper.

Question 404

[1 marks]How sound travels through air, and why an explosion on the moon cannot be heard
An explosion happens on the surface of the moon. An astronaut standing nearby, outside any spacecraft, cannot hear it. Why exactly is this?
  1. ASound does travel on the moon, but it is always too quiet for an astronaut to notice.
  2. BGravity on the moon is too weak to let sound waves form at all, since forming any wave is assumed here to need a strong enough gravitational pull on the particles.
  3. CSound needs a material medium of particles to travel through, and the moon has no atmosphere for the sound to travel through.
  4. DThe explosion is always too far away from any astronaut for sound to reach them.

Question 501

[2 marks]Comparing X-rays and infrared radiation, and calculating infrared frequency from wavelength
Which of the following correctly states a genuine difference between X-rays and infrared radiation (rather than a property they share)?
  1. AX-rays are transverse waves, while infrared radiation is a longitudinal wave.
  2. BX-rays have a much shorter wavelength and higher frequency than infrared radiation.
  3. CX-rays cannot travel through a vacuum, while infrared radiation can.
  4. DX-rays travel at the speed of light in a vacuum, while infrared radiation does not.

Question 502

[1 marks]Comparing X-rays and infrared radiation, and calculating infrared frequency from wavelength
X-rays and infrared radiation both belong to the same family of waves. Name that family.

Answer this when you sit the paper.

Question 503

[2 marks]Comparing X-rays and infrared radiation, and calculating infrared frequency from wavelength
Calculate the frequency of infrared radiation of wavelength 1×10−51\times10^{-5} m, given that the speed of light c = 3×1083\times10^8 m/s.

Answer this when you sit the paper.

Question 601

[2 marks]Properties of a plane-mirror image, and completing a ray diagram to locate it
Which of the following correctly states two properties of the image formed when an object is placed in front of a plane mirror?
  1. AThe image is virtual but smaller than the object.
  2. BThe image is real and the same size as the object, but inverted.
  3. CThe image is virtual and the same size as the object.
  4. DThe image is real and magnified compared with the object.

Question 602

[1 marks]Properties of a plane-mirror image, and completing a ray diagram to locate it
Object A stands in front of a plane mirror. State how the perpendicular distance of A's image behind the mirror compares with A's own distance in front of the mirror.

Answer this when you sit the paper.

Question 603

[2 marks]Properties of a plane-mirror image, and completing a ray diagram to locate it
To locate object A's image in a plane mirror by ray construction, two rays from A are drawn striking the mirror and reflecting toward the observer's eye, then extended backward (as dashed lines) behind the mirror. What determines where these backward-extended lines meet?
  1. AThey are extended until they cross at a single point behind the mirror; that crossing point is the image.
  2. BThey are extended until they reach the edge of the page, and the image is placed there regardless of where they cross.
  3. COnly one reflected ray is ever needed, since a single ray alone fixes the image's exact position.
  4. DThe lines are extended forward, in front of the mirror, since a plane mirror image always forms in front of it.

Question 701

[1 marks]Lenz's law, what it conserves, and why electrical energy is transmitted at high a.c. voltages
Which statement correctly gives Lenz's law?
  1. AThe magnitude of an induced e.m.f. is always equal to the rate of change of the magnetic flux, regardless of direction.
  2. BThe direction of an induced e.m.f./current is always such as to oppose the change in magnetic flux that produces it.
  3. CAn induced current always flows in the same direction as the magnetic flux that produces it.
  4. DInduced currents only appear when a conductor is stationary within an unchanging magnetic field.

Question 702

[1 marks]Lenz's law, what it conserves, and why electrical energy is transmitted at high a.c. voltages
State what physical quantity is conserved according to Lenz's law.

Answer this when you sit the paper.

Question 703

[2 marks]Lenz's law, what it conserves, and why electrical energy is transmitted at high a.c. voltages
Electrical energy is transmitted over long distances at a high voltage rather than a low voltage, for a given power delivered. Why does this reduce energy losses?
  1. AA higher voltage reduces the total power that needs to be delivered to consumers, so less energy has to be sent through the cables in the first place, regardless of the current flowing.
  2. BA higher voltage always produces a lower resistance in the transmission cables themselves.
  3. CA higher voltage makes electrons in the cable move faster than the speed of light, avoiding energy loss entirely.
  4. DA higher voltage means a lower current is needed for the same power, and a lower current produces less heat loss in the cables (since power loss is proportional to current squared).

Question 704

[1 marks]Lenz's law, what it conserves, and why electrical energy is transmitted at high a.c. voltages
Electrical energy is transmitted as a.c. rather than d.c. mainly because...
  1. Aa.c. voltage can easily be stepped up and down using transformers, which need a changing current to work.
  2. Ba.c. always travels faster along a cable than d.c. does.
  3. Ca.c. cables need no insulation, unlike d.c. cables, because an alternating voltage never builds up a steady charge on the cable's surface.
  4. Da.c. is always cheaper to generate than d.c., regardless of the distance it must travel.

Question 801

[1 marks]Naming and using circuit components, and reading a resistor's value from its colour code
In a circuit diagram, component A is drawn as a plain rectangular box symbol, in series with component B and a battery. Name component A.

Answer this when you sit the paper.

Question 802

[1 marks]Naming and using circuit components, and reading a resistor's value from its colour code
In the same circuit diagram, component B is drawn as two short parallel lines, in series with component A and a battery. Name component B.

Answer this when you sit the paper.

Question 803

[1 marks]Naming and using circuit components, and reading a resistor's value from its colour code
A capacitor is connected in series in a simple circuit with a resistor and a battery. Which of these is a genuine use of the capacitor in such a circuit?
  1. AIt permanently converts direct current into mechanical motion.
  2. BIt amplifies the battery's voltage far beyond its rated value.
  3. CIt generates its own current, independent of the battery, by continuously converting stored mechanical energy into electrical energy.
  4. DIt stores electrical charge/energy, and can smooth or filter the current.

Question 804

[2 marks]Naming and using circuit components, and reading a resistor's value from its colour code
A resistor's colour bands, read in order, are Red, Green, Orange. Using the standard colour code (Red=2, Green=5, Orange=3), where the third band is a multiplier of 10 to that power, determine the resistor's value X.

Answer this when you sit the paper.

Question 901

[1 marks]Momentum, a spring-extension experiment and Hooke's law, the principle of moments on a see-saw, and states of equilibrium
State the two physical quantities that are multiplied together to calculate momentum.

Answer this when you sit the paper.

Question 902

[2 marks]Momentum, a spring-extension experiment and Hooke's law, the principle of moments on a see-saw, and states of equilibrium
Momentum is a vector quantity, even though mass (one of the two quantities used to calculate it) is a scalar. Why is this?
  1. ABecause momentum only has a direction when the object involved is moving in a circle, since straight-line motion is assumed here to have no direction of its own.
  2. BBecause mass itself secretly has a direction, even though it is usually treated as a scalar.
  3. CBecause velocity, the other quantity used to calculate momentum, has both a magnitude and a direction, and this direction carries over to the momentum.
  4. DBecause momentum is calculated by adding mass and velocity together, rather than multiplying them.

Question 903

[2 marks]Momentum, a spring-extension experiment and Hooke's law, the principle of moments on a see-saw, and states of equilibrium
Calculate the momentum of a car of mass 500 kg moving at 8 m/s.

Answer this when you sit the paper.

Question 904

[1 marks]Momentum, a spring-extension experiment and Hooke's law, the principle of moments on a see-saw, and states of equilibrium
State the equation relating the extension x of a spring to the applied force F and the spring constant k.

Answer this when you sit the paper.

Question 905

[1 marks]Momentum, a spring-extension experiment and Hooke's law, the principle of moments on a see-saw, and states of equilibrium
A spring obeys Hooke's law. If the load on it is doubled, within its elastic limit, what happens to its extension?

Answer this when you sit the paper.

Question 906

[1 marks]Momentum, a spring-extension experiment and Hooke's law, the principle of moments on a see-saw, and states of equilibrium
Which statement correctly gives Hooke's law?
  1. AThe extension of a spring is directly proportional to the applied force/load, provided the elastic limit is not exceeded.
  2. BA spring returns to its original length only if the applied force is removed within one second.
  3. CThe extension of a spring is always exactly equal to the applied force, in any unit system, with no constant of proportionality needed at all.
  4. DA spring's extension is inversely proportional to the applied force, provided the elastic limit is not exceeded.

Question 907

[2 marks]Momentum, a spring-extension experiment and Hooke's law, the principle of moments on a see-saw, and states of equilibrium
A load of 5 N added to a steel spring increases its length from 9.5 cm to 29.5 cm. Calculate the spring constant of the spring.

Answer this when you sit the paper.

Question 908

[3 marks]Momentum, a spring-extension experiment and Hooke's law, the principle of moments on a see-saw, and states of equilibrium
Two students of mass 35 kg and 42 kg balance a uniform see-saw, sitting on either side of its pivot. The 35 kg student sits 1.2 m from the pivot. Calculate the distance from the pivot at which the 42 kg student must sit for the see-saw to balance.

Answer this when you sit the paper.

Question 909

[1 marks]Momentum, a spring-extension experiment and Hooke's law, the principle of moments on a see-saw, and states of equilibrium
For a uniform see-saw beam balanced on a central pivot, where is the beam's own centre of mass located?

Answer this when you sit the paper.

Question 910

[1 marks]Momentum, a spring-extension experiment and Hooke's law, the principle of moments on a see-saw, and states of equilibrium
Which of the following is a genuine everyday application of the principle of moments?
  1. AA loudspeaker, where an electrical signal is converted into sound.
  2. BA wheelbarrow, where a load is lifted by applying an effort at the handles about the wheel's pivot.
  3. CA torch, where a battery powers a bulb through a simple switch.
  4. DA thermometer, where a liquid expands to show temperature, working through thermal expansion rather than through any turning effect of a force.

Question 911

[1 marks]Momentum, a spring-extension experiment and Hooke's law, the principle of moments on a see-saw, and states of equilibrium
A ball rests in a shallow concave dip on a platform, such that any small displacement raises the ball's centre of mass, making it roll back to its original position. State its state of equilibrium.

Answer this when you sit the paper.

Question 912

[1 marks]Momentum, a spring-extension experiment and Hooke's law, the principle of moments on a see-saw, and states of equilibrium
A ball rests balanced on top of a slight convex bump on a platform, such that any small displacement lowers the ball's centre of mass, making it roll further away from its original position. State its state of equilibrium.

Answer this when you sit the paper.

Question 913

[1 marks]Momentum, a spring-extension experiment and Hooke's law, the principle of moments on a see-saw, and states of equilibrium
A ball rests on a plain flat, horizontal platform, such that a small displacement neither raises nor lowers the ball's centre of mass. State its state of equilibrium.

Answer this when you sit the paper.

Question 914

[2 marks]Momentum, a spring-extension experiment and Hooke's law, the principle of moments on a see-saw, and states of equilibrium
A ball resting in a shallow dip returns to its original position after being slightly displaced. Why does this happen?
  1. AThe small displacement raises the ball's centre of mass, and its weight then pulls it back down toward the lowest point, its original position.
  2. BThe small displacement lowers the ball's centre of mass, so gravity pulls it further away from its original position.
  3. CFriction alone, with no role for the ball's centre of mass, is what pulls the ball back to its original position.
  4. DThe ball returns to its original position only because the platform is perfectly smooth and frictionless, with friction otherwise needed to hold it in place at all.

Question 1001

[1 marks]Displacement-time graph analysis, forces on a moving bus, and a block-and-tackle pulley system
Define speed.

Answer this when you sit the paper.

Question 1002

[3 marks]Displacement-time graph analysis, forces on a moving bus, and a block-and-tackle pulley system
A car's displacement-time graph rises in a straight line from the origin O (0 hr, 0 m) to point A (3 hr, 10 m), stays flat from A to point B (6 hr, 10 m), then falls in a straight line from B to point C (9 hr, 0 m). Which of the following correctly describes the car's motion?
  1. AThe car is stationary for the whole journey shown, since it ends up back where it started, meaning both its overall displacement and its actual distance travelled must be zero.
  2. BThe car moves away from the start, speeding up continuously, then instantly teleports back to the start at t = 9 hr.
  3. CThe car accelerates uniformly the whole time from O to C, never travelling at a constant velocity.
  4. DThe car moves away from the start at a constant velocity (O to A), is stationary (A to B), then returns to the start at a constant velocity in the opposite direction (B to C).

Question 1003

[3 marks]Displacement-time graph analysis, forces on a moving bus, and a block-and-tackle pulley system
A car's displacement-time graph rises from O (0 hr, 0 m) to A (3 hr, 10 m), stays flat from A to B (6 hr, 10 m), then falls from B to C (9 hr, 0 m). Calculate the total distance travelled by the car over the whole 9 hours.

Answer this when you sit the paper.

Question 1004

[1 marks]Displacement-time graph analysis, forces on a moving bus, and a block-and-tackle pulley system
A car's displacement-time graph stays flat, at a constant 10 m, between t = 3 hr (point A) and t = 6 hr (point B). On the corresponding velocity-time graph, state the car's velocity during this interval.

Answer this when you sit the paper.

Question 1005

[1 marks]Displacement-time graph analysis, forces on a moving bus, and a block-and-tackle pulley system
Fig 10.2 shows a moving bus with horizontal force P acting to the left and force Q acting to the right. When the bus travels along a straight road at constant speed, how do the magnitudes of P and Q compare?

Answer this when you sit the paper.

Question 1006

[1 marks]Displacement-time graph analysis, forces on a moving bus, and a block-and-tackle pulley system
Fig 10.2 shows a moving bus with horizontal force P acting to the left and force Q acting to the right. When the bus is accelerating (speeding up), how do the magnitudes of P and Q compare?

Answer this when you sit the paper.

Question 1007

[1 marks]Displacement-time graph analysis, forces on a moving bus, and a block-and-tackle pulley system
A bus travels around a curve at a constant speed. State the direction of the resultant force acting on the bus.

Answer this when you sit the paper.

Question 1008

[2 marks]Displacement-time graph analysis, forces on a moving bus, and a block-and-tackle pulley system
A bus travels around a curve at a constant speed. Even though its speed does not change, why is there still a resultant force acting on it?
  1. AThere is no resultant force in this situation; the question's premise is incorrect, since a bus moving at a constant speed can never have any acceleration at all.
  2. BBecause the road surface on a curve always applies more friction than a straight road, regardless of the bus's motion.
  3. CBecause the bus's engine must work harder on a curve, which alone creates a resultant force.
  4. DBecause the bus's direction of travel keeps changing, so its velocity is changing, meaning there is an acceleration and hence a resultant force.

Question 1009

[1 marks]Displacement-time graph analysis, forces on a moving bus, and a block-and-tackle pulley system
A block-and-tackle pulley system has 2 rope sections supporting its lower, movable pulley, from which the load hangs. State the velocity ratio of this system.

Answer this when you sit the paper.

Question 1010

[2 marks]Displacement-time graph analysis, forces on a moving bus, and a block-and-tackle pulley system
In a block-and-tackle pulley system, a 1 kg load is raised using an effort of 8 N (take g = 10 N/kg). Calculate the mechanical advantage of the system.

Answer this when you sit the paper.

Question 1011

[2 marks]Displacement-time graph analysis, forces on a moving bus, and a block-and-tackle pulley system
A block-and-tackle pulley system has a velocity ratio of 2 and a mechanical advantage of 1.25. Calculate its efficiency.

Answer this when you sit the paper.

Question 1012

[1 marks]Displacement-time graph analysis, forces on a moving bus, and a block-and-tackle pulley system
Which of these would genuinely increase the efficiency of a block-and-tackle pulley system?
  1. AAdding extra, heavier pulleys to the system.
  2. BIncreasing the load being lifted, since a heavier load is assumed here to always make any pulley system work more efficiently.
  3. CUsing a longer rope between the pulleys.
  4. DLubricating the pulley axles to reduce friction.

Question 1101

[2 marks]Charging by induction, electric field lines, and current from charge and time; earthing and two-pin plug safety; potential difference, bulb brightness, and electrical energy
A negatively-charged polythene rod is held near, but not touching, an isolated metal sphere. The far side of the sphere is then momentarily earthed, before the earth connection is removed (while the rod is still nearby), and finally the rod is taken away. Which sequence correctly explains how the sphere ends up positively charged?
  1. AEarthing the sphere adds extra electrons to it, which then become positive once the earth wire is removed.
  2. BThe rod's charge has no effect on the sphere at all; the sphere becomes charged only once it is earthed.
  3. CThe rod repels the sphere's free electrons to its far side; earthing lets those electrons flow away; removing the earth connection (rod still near) traps the remaining positive charge on the sphere.
  4. DThe rod directly transfers its own negative charge onto the sphere by touching it, even though the diagram clearly shows the rod held away from the sphere without any contact between them at any point.

Question 1102

[2 marks]Charging by induction, electric field lines, and current from charge and time; earthing and two-pin plug safety; potential difference, bulb brightness, and electrical energy
A charged polythene rod is held near an isolated metal sphere whose near side has become positively charged by induction. State the direction of the electric field lines drawn between the rod and the sphere (from which object to which).

Answer this when you sit the paper.

Question 1103

[2 marks]Charging by induction, electric field lines, and current from charge and time; earthing and two-pin plug safety; potential difference, bulb brightness, and electrical energy
A spark carries a charge of 2.4×10−72.4\times10^{-7} C between two materials in a time of 0.00015 s. Calculate the current that passes between them.

Answer this when you sit the paper.

Question 1104

[2 marks]Charging by induction, electric field lines, and current from charge and time; earthing and two-pin plug safety; potential difference, bulb brightness, and electrical energy
An appliance's metal casing is connected to earth by an earth wire. Why does this protect a user from an electric shock if a fault occurs?
  1. AThe earth wire only protects the appliance's internal components, and plays no role in protecting the user.
  2. BThe earth wire permanently stops any current at all from ever reaching the casing, under any circumstance.
  3. CIf a fault makes the live wire touch the casing, the large fault current flows safely to earth through the low-resistance earth wire, blowing the fuse and disconnecting the appliance, rather than passing through a user touching the casing.
  4. DThe earth wire lowers the voltage of the live wire itself, making it safe to touch directly, in the same way a step-down transformer reduces a high mains voltage before it ever reaches the appliance's casing or any of its other internal components.

Question 1107

[2 marks]Charging by induction, electric field lines, and current from charge and time; earthing and two-pin plug safety; potential difference, bulb brightness, and electrical energy
An electrical appliance uses only a two-pin (unearthed) plug, yet is still considered safe to use. Suggest why.

Answer this when you sit the paper.

Question 1108

[1 marks]Charging by induction, electric field lines, and current from charge and time; earthing and two-pin plug safety; potential difference, bulb brightness, and electrical energy
Which of these correctly defines potential difference?
  1. AThe total charge that has passed a point in a circuit since it was switched on, measured cumulatively over the whole time the circuit has been running so far.
  2. BThe rate at which charge flows past a point in a circuit.
  3. CThe work done (energy transferred) per unit charge passing between two points in a circuit.
  4. DThe total energy stored in a battery, regardless of how much charge has flowed.

Question 1109

[1 marks]Charging by induction, electric field lines, and current from charge and time; earthing and two-pin plug safety; potential difference, bulb brightness, and electrical energy
State the SI unit of potential difference.

Answer this when you sit the paper.

Question 1110

[1 marks]Charging by induction, electric field lines, and current from charge and time; earthing and two-pin plug safety; potential difference, bulb brightness, and electrical energy
Two identical bulbs are to be connected to a fixed supply so as to give maximum brightness. Should they be connected in series or in parallel?

Answer this when you sit the paper.

Question 1111

[3 marks]Charging by induction, electric field lines, and current from charge and time; earthing and two-pin plug safety; potential difference, bulb brightness, and electrical energy
Two identical bulbs, each rated 75 W, are both lit together for 20 minutes. Calculate the total electrical energy they use.

Answer this when you sit the paper.

Question 1112

[1 marks]Charging by induction, electric field lines, and current from charge and time; earthing and two-pin plug safety; potential difference, bulb brightness, and electrical energy
State the commercial (everyday billing) unit for electrical energy.

Answer this when you sit the paper.

Question 1201

[3 marks]Force on parallel current-carrying conductors, the a.c. generator, full-wave rectification, and radioactivity
Two parallel, vertical conductors both carry current upward. Their magnetic fields overlap in the region between them. What happens to the two conductors as a result?
  1. AThey repel each other, since any two current-carrying conductors always repel.
  2. BNeither force acts, since the two conductors' magnetic fields simply cancel out completely everywhere.
  3. CThey rotate around each other rather than moving directly toward or away from each other.
  4. DThey attract each other, since parallel currents flowing in the same direction attract.

Question 1202

[1 marks]Force on parallel current-carrying conductors, the a.c. generator, full-wave rectification, and radioactivity
Which of the following does NOT affect the magnitude of the force on a current-carrying conductor placed near another parallel current-carrying conductor?
  1. AThe length of the conductors within each other's field.
  2. BThe colour of the conductor's outer insulation.
  3. CThe size of the current in each conductor.
  4. DThe distance between the two conductors.

Question 1203

[1 marks]Force on parallel current-carrying conductors, the a.c. generator, full-wave rectification, and radioactivity
In an a.c. generator, name the two components that maintain electrical contact between the rotating coil and the external circuit.

Answer this when you sit the paper.

Question 1204

[3 marks]Force on parallel current-carrying conductors, the a.c. generator, full-wave rectification, and radioactivity
In an a.c. generator, a coil rotates in a magnetic field between the poles of a permanent magnet. Explain why the current produced is alternating rather than direct.
  1. AThe current is alternating only because the slip rings themselves generate a changing voltage, independent of the coil's motion.
  2. BAs the coil rotates, each side alternately cuts the field lines moving up then down (relative to the field) every half rotation, reversing the direction of the induced e.m.f. and current each half turn.
  3. CThe coil produces a direct current, which only appears alternating once it reaches the external circuit.
  4. DThe permanent magnet's poles swap position every half rotation, which is what reverses the current, even though the magnet itself does not move at all during the generator's normal operation.

Question 1205

[1 marks]Force on parallel current-carrying conductors, the a.c. generator, full-wave rectification, and radioactivity
State the effect responsible for the e.m.f. induced in the rotating coil of an a.c. generator.

Answer this when you sit the paper.

Question 1206

[1 marks]Force on parallel current-carrying conductors, the a.c. generator, full-wave rectification, and radioactivity
A bridge of four diodes connects an a.c. source to a load, converting the a.c. supply to a (pulsating) direct current at the output. Name this process.

Answer this when you sit the paper.

Question 1207

[3 marks]Force on parallel current-carrying conductors, the a.c. generator, full-wave rectification, and radioactivity
A bridge of four diodes converts an a.c. supply into a direct current at its output. How is this achieved?
  1. AOn each half of the a.c. cycle, only the pair of diodes that are forward-biased for that half conducts, always directing current through the load in the same direction.
  2. BThe bridge converts a.c. to d.c. by storing charge in the diodes themselves and releasing it steadily.
  3. CAll four diodes conduct at all times, regardless of which half of the a.c. cycle is applied, since a diode bridge is wired to ignore the direction of current flow entirely.
  4. DThe diodes block current completely during one half of the cycle, so no current at all flows through the load half the time.

Question 1208

[2 marks]Force on parallel current-carrying conductors, the a.c. generator, full-wave rectification, and radioactivity
In a full-wave diode-bridge rectifier with diodes D1, D2, D3 and D4, terminal A of the a.c. source is positive (and B is negative). Which two diodes conduct?

Answer this when you sit the paper.

Question 1209

[1 marks]Force on parallel current-carrying conductors, the a.c. generator, full-wave rectification, and radioactivity
State the penetration power of alpha particles (what stops them).

Answer this when you sit the paper.

Question 1210

[1 marks]Force on parallel current-carrying conductors, the a.c. generator, full-wave rectification, and radioactivity
State the penetration power of beta particles (what stops them).

Answer this when you sit the paper.

Question 1211

[1 marks]Force on parallel current-carrying conductors, the a.c. generator, full-wave rectification, and radioactivity
State the penetration power of gamma rays (what stops them).

Answer this when you sit the paper.

Question 1212

[1 marks]Force on parallel current-carrying conductors, the a.c. generator, full-wave rectification, and radioactivity
Which of the following is a genuine use of radioactive isotopes in medicine?
  1. AAs a replacement for anaesthetic during surgery.
  2. BAs a coolant in hospital refrigeration units.
  3. CAs tracers to diagnose disorders/image internal organs.
  4. DAs the main power source for hospital lighting systems.

More sittings of this paper

The answers, and why they are the answers

Sit the paper here to see which ones you got right. Danho explains every question, keeps your score, and works without a connection.

Get it on Google PlayDownload on the App Store