May/June 2015

Is mass a scalar quantity or a vector quantity, and is acceleration a scalar quantity or a vector quantity?

Physical quantities and measurement techniques

When a car goes round a corner at speed, it may topple over. The stability of a car depends on the height of its centre of mass and the distance between its front wheels. Which factors give the car the greatest stability?

Centre of gravity

A cyclist moves along a level track at steady speed. The work done by the cyclist is equal to

Work

A mass of $2.0\,\text{kg}$ has $300\,\text{J}$ of kinetic energy. Determine the speed of the mass.

Energy

The diagram represents a basic model of a car’s braking system. A force of $20\,\text{N}$ is applied to piston P. This produces a force $F$ on piston Q. Piston P has an area of $5.0\,\text{cm}^2$ and piston Q has an area of $25\,\text{cm}^2$. What is the force $F$?

Pressure

The diagrams illustrate liquids held in containers. Which column of liquid produces the greatest pressure on the bottom of its container?

Pressure

One end of a solid bar is heated. By what process is thermal energy moved to the opposite end of the bar?

Conduction

In solar heating panels, the tubes absorb the Sun’s radiation to heat water. Why are the tubes coated black?

Radiation

What causes the constriction in a clinical thermometer?

Thermal expansion of solids, liquids and gases

For a liquid-in-glass thermometer, the liquid column measures $2.0\,\text{cm}$ at $0\,^\circ\text{C}$ and rises to $10.0\,\text{cm}$ when it is heated to $100\,^\circ\text{C}$. Starting from P, what is the length of the liquid column at $30\,^\circ\text{C}$?

Thermal expansion of solids, liquids and gases

At $20\,^\circ\text{C}$, which substance in the table is in the liquid state?

States of matter

To measure the diameter and the length of a thin wire, about $50\ \text{cm}$ long, as accurately as possible, which instruments are the best to use?

Physical quantities and measurement techniques

In what situation do sound waves not propagate?

Sound

A wave in a ripple tank moves from a deeper region into a shallower region and refracts. Which wave properties become smaller as the wave enters the shallow region?

General properties of waves

A ray of light is incident on the surface of a glass block, as illustrated in the diagram below. The refractive index of the glass is $1.5$. As the light ray enters the glass, its direction changes. What is the angle $x$ through which the ray moves?

Refraction of light

When a thin converging lens is used as a magnifying glass, an image is produced. Which description of the image is correct?

Thin lenses

A light ray moves from X to Y through an optical fibre. At Y, the angle of incidence is larger than the critical angle. In which direction does the light ray move after arriving at point Y?

Refraction of light

At position 1, one end of a rod attracts the N-pole of a bar magnet. At position 2, the same end of the rod attracts the S-pole of the bar magnet. What material is the rod made of, and what pole is at end P of the rod in position 1?

Simple magnetism and magnetic fields

A metal ring is used to shield a piece of equipment from a magnetic field. Which metal ought to be used for the ring, and why?

Simple magnetism and magnetic fields

The diagram illustrates the magnetic field pattern produced by a current in a solenoid. If the current in the solenoid is increased, at which position does the magnetic field strength increase?

Magnetic effect of a current

The diagram displays a circuit. Which circuit diagram represents this circuit?

Circuit diagrams and circuit components

A charge of $7.5\,\text{C}$ passes through a resistor in $5.0\,\text{s}$. A student has ammeters of several different ranges available to measure the current in the resistor. Which ammeter range would be the most suitable?

Electrical current

A student moves at a steady speed. He needs $100\ \text{s}$ to complete $160$ paces. Each pace measures $0.80\ \text{m}$. What distance does the student cover in $50\ \text{s}$?

Motion

Three identical cells are linked in parallel to a resistor. What advantage is gained by using three cells in parallel instead of one cell?

Series and parallel circuits

When a camera flash is operated, a charge of $1.5\,\text{C}$ passes through the flash-tube in $0.0030\,\text{s}$. The average potential difference across the flash-tube is $3600\,\text{V}$. Calculate the electrical energy delivered to the flash-tube and the average power delivered.

Electrical quantities

A wire with length $1.0\,\text{m}$ and cross-sectional area $0.40\,\text{mm}^2$ has a resistance of $2.0\,\Omega$. What resistance would a $0.50\,\text{m}$ length of wire have, if it is made from the same material and has a cross-sectional area of $0.80\,\text{mm}^2$?

Resistance

The diagram illustrates three resistors connected in parallel. What is the total resistance?

Series and parallel circuits

In which circuit does the voltmeter show a reading of $7.2\,\text{V}$?

Electric circuits

The diagram gives the details printed on an electric kettle. $240\,\text{V}\quad 50\,\text{Hz}$ $600\,\text{W}\quad 700\,\text{cm}^3$ What is the frequency of the electricity supply used to power the kettle?

Uses of electricity

A magnet is positioned close to a solenoid which is connected to a sensitive centre-zero ammeter. The magnet is then pushed in the direction of the solenoid. It speeds up, then travels with constant speed, then slows down and comes to rest inside the solenoid. At what point does the ammeter reading become zero?

Electromagnetic induction

A radioactive substance undergoes decay in the following way: $^{Y}_{Z}\text{L} \rightarrow {}^{Y}_{Z+1}\text{M} + x$ Which particle is $x$?

The three types of emission

A factory makes plastic sheets without stopping. To check how thick the sheets are, a radioactive isotope and a detector are used. Which source is most suitable to use?

The three types of emission

A source contains a radioactive material. When the radioactive source is not present, a detector measures a background count rate of $20$ counts per minute. The source is then placed in a fixed position close to the detector. At first, a count rate of $520$ per minute is measured. What count rate would be measured after a time of two half-lives of the radioactive source?

Half-life

A stone’s mass is measured on Earth with a pan balance. Its weight is measured with a newton meter. On the Moon, would these readings be the same or different?

Mass and weight

The nucleus has $94$ protons and $240$ nucleons. It releases an alpha-particle. How many protons and how many neutrons are present in the nucleus that is formed?

The three types of emission

The table gives the weights and masses of four objects on different planets. On which planet is the gravitational field strength greatest?

Mass and weight

Four forces are applied at a point, as illustrated. What is the magnitude of the resultant force?

Balanced and unbalanced forces

A student lets a table-tennis ball fall through the air from rest. What happens to the ball’s velocity and acceleration during the first few seconds after it is released?

Motion

The mass and volume of four distinct objects are plotted in the diagram shown. Which object has the lowest density?

Density

Newton’s third law describes two quantities that are equal in magnitude and opposite in direction. What unit is used for these two quantities?

Forces

Which quantity is a scalar?

Physical quantities and measurement techniques

The diagrams illustrate liquids in containers. Which column of liquid produces the largest pressure at the base of its container?

Pressure

The graph illustrates how the pressure of a fixed mass of gas changes with volume when the temperature is kept constant. What volume does the gas have when the pressure is 25 kPa?

Pressure

A rocket with total mass $M$ is moving at speed $v$. Its engine is switched on and fuel is consumed. The rocket’s mass falls to $\frac{M}{2}$ and its speed rises to $2v$. What happens to the kinetic energy of the rocket?

Energy

A builder raises eight slabs from the ground onto the back of a lorry that is 1.5 m above the ground. The complete time for this is 48 s, and the weight of each slab is 200 N. What useful power does the builder generate?

Power

A metal bar with a solid structure is heated at one end. By what process is thermal energy passed to the opposite end of the bar?

Conduction

An electrical heater is put into a beaker containing cold oil, as illustrated. The heater is then switched on. What change occurs to the liquid at X?

Convection

The tubes within solar heating panels absorb the Sun’s radiation to heat water. Why is black paint used on the tubes?

Radiation

For a liquid-in-glass thermometer, the liquid column measures 2.0 cm in length at $0^{\circ}\text{C}$ and becomes 10.0 cm longer when it is heated to $100^{\circ}\text{C}$. Starting from P, what is the length of the liquid column at $30^{\circ}\text{C}$?

Thermal expansion of solids, liquids and gases

At $20^{\circ}\text{C}$, which substance in the table is in the liquid state?

States of matter

Which diagram shows the change in the arrangement of the molecules in a solid as the substance melts?

Particle model

A thin wire, which is roughly $50\text{ cm}$ long, has its diameter and length measured with maximum precision possible. Which instruments are most suitable to use?

Physical quantities and measurement techniques

A quantity of gas is enclosed in a sealed container. The gas is cooled while the container’s volume remains unchanged. What occurs to the gas molecules?

Particle model

Within a liquid, a number of high-energy molecules escape from the surface even though the liquid is not hot enough for bubbles to be produced. What is the name of this process?

Melting, boiling and evaporation

A pupil places $37\,\text{g}$ of ice at $0\,^{\circ}\text{C}$ into $100\,\text{g}$ of water at $30\,^{\circ}\text{C}$. After mixing, the water and the melted ice both have a final temperature of $0\,^{\circ}\text{C}$. There is no transfer of heat to the surroundings or from them. The specific heat capacity of water is $4.2\,\text{J g}^{-1}\,^{\circ}\text{C}^{-1}$. Determine the specific latent heat of ice.

Melting, boiling and evaporation

For an object of mass $2.0\,\text{kg}$, its heat capacity is $C$. The energy required to

Specific heat capacity

A ball floating in a ripple tank starts to oscillate up and down as a wave moves underneath it. The ball does not travel horizontally. Which statement is correct?

General properties of waves

A light ray travelling in glass strikes the surface at angle $c$. Angle $c$ is the critical angle. Which diagram shows the path of the light?

Refraction of light

A ray of light strikes the surface of a glass block, as illustrated in the diagram below. The refractive index of the glass is $1.5$. As the light ray enters the glass, its direction changes. Through what angle $x$ does the ray deviate?

Refraction of light

A thin converging lens is acting as a magnifying glass and produces an image. Which description of the image is correct?

Thin lenses

Which section of the electromagnetic spectrum is used to send television signals from satellites?

Electromagnetic spectrum

In what situation do sound waves not travel?

Sound

A cyclist completes a journey that lasts $25\text{ s}$. The diagram shows how the distance travelled from her starting point changes with time. What is her average speed for the entire journey?

Motion

Two sound waves X and Y are being compared. X has the higher frequency, while Y has the larger amplitude. How do the loudness and pitch of sound wave Y compare with those of X?

Sound

A metal ring shields a piece of equipment from a magnetic field. Which metal should be chosen for the ring, and why?

Simple magnetism and magnetic fields

A positively charged rod is moved close to an isolated, uncharged conducting sphere. What charges appear on sides X and Y of the sphere?

Electrical charge

The diagram shows a circuit. In which position should an ammeter be connected to measure the lowest current?

Action and use of circuit components

A pair of resistors with resistances $30\,\Omega$ and $60\,\Omega$ are connected in parallel. The current through the $30\,\Omega$ resistor is $0.60\,\text{A}$. What potential difference is across the $60\,\Omega$ resistor?

Series and parallel circuits

The diagram contains three resistors arranged in series and joined to a battery. A voltmeter is connected across each resistor, and two of the voltages are given. What is the potential difference (p.d.) across the resistor $R$?

Series and parallel circuits

A teacher pushes a magnet in and out of a coil of wire, as shown, to show electromagnetic induction. Which statement is correct?

Electromagnetic induction

A transformer is made from two coils wound around a metallic core. What kind of voltage is provided to the transformer, and which metal is used to construct the core?

The transformer

A nucleus of $^{215}_{84}\text{Po}$ undergoes decay by releasing an alpha-particle, and the new nucleus then undergoes decay by releasing a beta-particle. What are the nucleon number and proton number of the final nucleus?

The three types of emission

A radioactive substance undergoes decay by the following process: $^{Y}_{Z}\text{L} \rightarrow \;^{Y}_{Z+1}\text{M} + x$. What particle is $x$?

The three types of emission

A car sets off and starts moving. It then increases its speed until it attains a steady speed. It goes on travelling at this steady speed for the remainder of the trip. What happens to the acceleration and what happens to the velocity of the car during the journey?

Motion

The half-life of a radioactive isotope is $24\,\text{hours}$. A sample of this isotope gives an initial count rate of $720$ counts per second. How long will it take for the count rate to decrease to $90$ counts per second?

Half-life

A metal ball with mass $0.30\text{ kg}$ and weight $3.0\text{ N}$ is kept beneath the oil surface. It is acted on by an upward force of $0.30\text{ N}$. After the ball is released, what is its initial acceleration?

Balanced and unbalanced forces

A student lets go of a table-tennis ball from rest in air. What happens to the ball’s velocity and to its acceleration during the first few seconds after it is released?

Motion

The Earth moves round the Sun in a circular path with constant speed. Which arrows indicate the direction of the Earth’s acceleration and the direction of the Earth’s velocity?

Circular motion

A pan balance is used to determine the mass of a stone on Earth. A newton meter is used to determine the weight of the stone. Would the readings be the same or different on the Moon?

Mass and weight

A beam of uniform density is supported on a pivot at its midpoint. Two weights are then positioned on the beam as illustrated, and an upward force $F$ keeps the beam in equilibrium. What is the magnitude of $F$?

Turning effect of forces

Fig. 1.1 is a distance-time graph showing cyclists A and B. They set off together in a 500 m race, but they cross the finish line at different times.

Motion

A student draws a diagram showing the molecules in a liquid, as in Fig. 10.1.

Melting, boiling and evaporation

A student builds a model of an atom. Inside the model there are 24 electrons, 25 protons and 26 neutrons. Some of these particles are located in a nucleus at the centre of the model.

The nuclear model of the atom

Fig. 2.1 shows a student carrying out a press-up. An upward total force $F$ acts on his hands, and an upward force also acts on his toes. The student’s weight is 600 N, and this force acts downward through his centre of mass.

Turning effect of forces

An experiment is set up to investigate how the pressure of a fixed mass of air at room temperature changes with volume. Fig. 3.1 shows the apparatus in use. The syringe is closed at one end, and the piston can move up and down while different metal weights are added.

Pressure

Fig. 4.1 shows a wave on a string, and the wave is moving to the right.

General properties of waves

Fig. 5.1 shows a ray of light as it enters an optical fibre and travels through it.

Refraction of light

Fig. 6.1 illustrates a circuit made up of a resistor linked to a 6.0 V power supply and a lamp L. The resistor has a resistance of $60\,\Omega$. The lamp is marked 6.0 V, 0.90 W.

Series and parallel circuits

Fig. 7.1 shows a straightforward setup for demonstrating electromagnetic induction. The coil is joined to two light-emitting diodes (LEDs). The magnet moves in and then out of the coil.

Electromagnetic induction

Fig. 8.1 gives the basic layout of a cathode-ray oscilloscope (c.r.o.). Several components are missing. Electrons are released from the filament by thermionic emission.

Uses of an oscilloscope

Fig. 9.1 shows a satellite orbiting the Earth.

Motion

The arrangement in Fig. 1.1 is set up to measure how far a spring extends. Fig. 1.1 shows a spring hanging from a support, a mass fixed to its lower end and a vertical scale beside it. The diagram labels: spring, mass, scale.

Elastic deformation

Fig. 10.1 depicts a relay linked to a cell and a switch. The diagram identifies the coil, iron core, iron armature, pivot, and terminals A, B, C and D.

Magnetic effect of a current

In Fig. 11.1, a bungee jumper drops from a bridge over a river. The man begins at position A. The elastic cord first begins to stretch at position C, and he comes to rest for the first time at position D. Fig. 11.2 shows how the man's velocity varies with time $t$.

Motion

Fig. 2.1 depicts two engineers checking the length of a wall built from concrete. The wall has a height of $2.0\,\text{m}$, a length of $15\,\text{m}$ and a thickness of $0.25\,\text{m}$. Its weight is $180\,000\,\text{N}$ and its mass is $18\,000\,\text{kg}$.

Density

As shown in Fig. 3.1, water is heated by two different kettles. The picture includes an electric kettle and a gas-heated kettle with a gas burner. The information for both kettles is given in Fig. 3.2.

Energy, work and power

A metal can and a plastic bottle, each filled with liquid, are cooled by standing them in a jug of melting ice, as shown in Fig. 4.1. Each container holds $330\,\text{g}$ of the same liquid at $15\,^{\circ}\text{C}$.

Specific heat capacity

If a balloon is rubbed against hair, it becomes negatively charged. The balloon is shown in Fig. 5.1.

Electrical charge

Fig. 6.1 shows a basic a.c. generator. The diagram labels are: coil, N pole, S pole, rotation of coil, and output voltage. Fig. 6.2 shows how the alternating e.m.f. varies with time.

The a.c. generator

An electric hairdryer and an electric heater are linked to the mains supply, as illustrated in Fig. 7.1. The cable from the heater to the mains supply contains a live wire, a neutral wire and an earth wire.

Electrical safety

The hydrogen isotopes $^{1}_{1}\text{H}$ and $^{2}_{1}\text{H}$ are shown here. Fig. 8.1 contains a table for the counts of protons and neutrons in one nucleus of each isotope.

The atom

Fig. 9.1 illustrates the wavefronts of a water wave in deep water in a ripple tank. The frequency of the wave in deep water is $5.0\,\text{Hz}$.

General properties of waves

A student carries out an investigation into a ball bouncing on a bench.

Momentum

A rain-gauge is used to find the quantity of rain that falls. Fig. 2.1 shows a typical rain-gauge.

Physical quantities and measurement techniques

A student is finding the refractive index of the glass in a semi-circular block. The student uses the relation refractive index $= \frac{\sin(\text{angle of incidence})}{\sin(\text{angle of refraction})}$. The semi-circular glass block is shown for you in Fig. 3.1. You may make drawings on Fig. 3.1.

Refraction of light

A student measures how long a $1.5\,\text{V}$ cell can supply a constant current of $0.3\,\text{A}$.

Circuit diagrams and circuit components

Two students choose a $100\,\text{m}$ stretch to act as a running track on a school field.

Physical quantities and measurement techniques

A student explores how parachute area changes the time it takes to descend. He trims a square from an A4 sheet of paper to form the parachute, then fastens it to an eraser with four equal-length pieces of thin string, as shown in Fig. 2.1. An A4 sheet of paper is the same size as one page of the examination paper. The student holds the top of the parachute against the ceiling. He lets it go and measures the time $t$ for the eraser to reach the floor.

Motion

A student uses a cathode-ray oscilloscope (c.r.o.) to measure a voltage.

Uses of an oscilloscope

A series of readings is to be taken so that a cooling curve can be plotted to show how fast hot water in a test tube cools.

Transfer of thermal energy