Physics Paper 1

What happens to the mass of ice when it melts and evaporates?

The mass stays the same. 10 g of ice produces 10 g of water vapour.

What is an example of a contact force?

Upthrust.

What property affects the gravitational field strength of an object?

Mass. More massive objects have stronger gravitational fields.

What is an NTC thermistor?

A component whose resistance decreases as its temperature increases.

How do you calculate distance travelled?

Distance = speed × time.

A bird travels at 5.0 m/s for 240 seconds. Calculate its distance.

5.0 × 240 = 1200 m.

How does a magnet interact with copper and iron?

Copper is not attracted to an ordinary magnet. Iron is attracted to a magnet.

Why does atmospheric pressure decrease as altitude increases?

There are fewer air molecules above you, so their weight produces less pressure.

What is an example of a chemical change?

Burning wood or frying an egg.

What is an example of a physical change?

Melting ice or boiling water.

What is the difference between a physical and chemical change?

A physical change does not produce a new substance. A chemical change produces one or more new substances.

Mercury has a melting point of -40°C and a boiling point of 357°C. What state is it at -20°C and 300°C?

Liquid at both temperatures because both are between its melting and boiling points.

Which particles move when two objects become charged by friction?

Electrons move from one object to the other.

What type of charge is transferred during charging by friction?

Negative charge, because electrons are negatively charged.

What happens to the volume and pressure of a gas when its volume is halved at constant temperature?

The pressure doubles.

What is the moment of a force?

The turning effect of a force around a pivot.

How do you calculate the moment of a force?

Moment = force × perpendicular distance from the pivot.

A student weighing 500 N sits 0.8 m from a see-saw pivot. Calculate their moment.

500 × 0.8 = 400 Nm.

How do you calculate current at a junction?

Total current entering a junction equals total current leaving it.

A circuit has 5.0 A entering a junction and 3.5 A in one branch. Calculate the current in the other branch.

5.0 - 3.5 = 1.5 A.

What is an induced magnet?

A temporary magnet that becomes magnetic when placed in a magnetic field.

How do you calculate kinetic energy?

Kinetic energy = 0.5 × mass × speed².

A 10 kg dog runs at 14 m/s. Calculate its kinetic energy.

0.5 × 10 × 14² = 980 J.

What are the three main subatomic particles?

Protons, neutrons and electrons.

Where are protons and neutrons found in an atom?

In the nucleus.

What is the charge of a proton?

Positive (+1).

What is the charge of a neutron?

Neutral (0).

What is the charge of an electron?

Negative (-1).

What is the overall charge of an atom?

Neutral, because it has equal numbers of protons and electrons.

Why have atomic models changed over time?

New experimental evidence has led scientists to improve and change their models.

What is the correct order of the development of atomic models?

Thomson → Rutherford → Bohr.

What is the plum pudding model?

Thomson's model, which described electrons embedded in a sphere of positive charge.

What did Rutherford's alpha scattering experiment show?

Atoms have a small, positively charged nucleus and are mostly empty space.

What did Bohr suggest about electrons?

Electrons orbit the nucleus in fixed energy levels or shells.

How should an ammeter be connected in a circuit?

In series.

How should a voltmeter be connected in a circuit?

In parallel across the component.

What is the purpose of a variable resistor?

It changes the resistance of the circuit and therefore changes the current.

What happens to the resistance of a filament lamp as its temperature increases?

Its resistance increases.

Why does a filament lamp's resistance increase as current increases?

The filament gets hotter, causing more collisions between electrons and the positive ions in the metal lattice.

How do you calculate electrical power?

Power = potential difference × current.

How do you calculate energy transferred electrically?

Energy transferred = power × time.

How many seconds are in 2 minutes?

120 seconds.

A filament lamp has a potential difference of 5.0 V and a current of approximately 2.8 A. Calculate its power.

5.0 × 2.8 = 14 W.

A lamp transfers 14 W of power for 2 minutes. Calculate the energy transferred.

14 × 120 = 1680 J.

How can you make a fair test when comparing the strength of fridge magnets?

Keep variables such as the magnet size, paper type, paper size and fridge surface the same.

How can you compare the strength of fridge magnets using paper?

Place paper between the magnet and fridge, adding pieces until the magnet no longer holds them. The strongest magnet holds the most pieces.

Which fridge magnet was strongest in the 2022 paper?

Magnet C, because it held 26 pieces of paper, the highest number.

What is the direction of magnetic field lines outside a magnet?

From the north pole to the south pole.

What do magnetic field lines show?

The direction and strength of a magnetic field. Closer lines represent a stronger field.

How do you plot a magnetic field around a bar magnet using a plotting compass?

Draw around the magnet, place the compass near one pole, mark the direction of its needle, move the compass to the new position and repeat. Join the dots to show the field line.

How does the resistance of an LDR change when light intensity increases?

Resistance decreases.

How does the resistance of an LDR change as the distance from a lamp increases?

Resistance increases because light intensity decreases.

How can you improve the accuracy of an LDR experiment?

Use a ruler to measure distance carefully, keep other light sources constant and repeat measurements.

How can you improve the precision of an LDR experiment?

Take repeated readings at each distance and calculate a mean.

How do you calculate volume?

For a cuboid, volume = length × width × height.

A cube has sides of 5 cm. Calculate its volume.

5 × 5 × 5 = 125 cm³.

How do you calculate density?

Density = mass ÷ volume.

Which two factors determine density?

Mass and volume.

Water has a density of 1000 kg/m³. How would it compare with a material of density 520 kg/m³?

Water is denser. The material is less dense than water and can float if its overall average density is below water's.

Which material would be suitable for a simple solid toy boat carrying a heavy load: carbon fibre, oak, pine or plastic?

Pine, because it has the lowest density at 520 kg/m³, making it more likely to float.

What are balanced forces?

Forces that are equal in size and opposite in direction, giving a resultant force of zero.

What happens when the resultant force on an object is zero?

It stays stationary or continues moving at a constant velocity.

A swimmer has a forward force of 50 N and a resistive force of 50 N. Describe their motion.

The forces are balanced, so the swimmer stays at rest or continues at constant velocity.

What happens if the forward force on a swimmer increases but the resistive force stays the same?

There is a resultant forward force, so the swimmer accelerates forwards.

What does the gradient of a displacement-time graph represent?

Velocity.

What does the gradient of a velocity-time graph represent?

Acceleration.

What does the area under a velocity-time graph represent?

Displacement.

What does a displacement-time graph look like when an object moves forwards and backwards repeatedly at constant speed?

A repeated triangular pattern, with the gradient changing sign when the object changes direction.

What does a velocity-time graph look like when an object moves forwards and backwards repeatedly at constant speed?

Velocity alternates between positive and negative values.

How do you calculate weight?

Weight = mass × gravitational field strength.

A swimmer has a mass of 75 kg. Calculate their weight using a gravitational field strength of 10 N/kg.

75 × 10 = 750 N.

What is Hooke's law?

The extension of a spring is directly proportional to the force applied, provided its limit of proportionality is not exceeded.

How do you calculate spring constant?

Spring constant = force ÷ extension.

What is the unit of spring constant?

N/m.

A rope extends by 0.15 m when a force of 10 N is applied. Calculate its spring constant.

10 ÷ 0.15 = 66.7 N/m, or 67 N/m to 2 significant figures.

How do you calculate elastic potential energy stored in a stretched spring?

Elastic potential energy = 0.5 × force × extension.

A rope stretches by 0.60 m under a force of 40 N. Calculate its elastic potential energy.

0.5 × 40 × 0.60 = 12 J.

What is the elastic limit?

The point beyond which a material will not return to its original shape when the force is removed.

What is plastic deformation?

A permanent change in shape when a material is stretched or deformed beyond its elastic limit.

A spring is stretched but does not return to its original length. What has happened?

It has undergone plastic deformation.

How can you estimate extension when a spring is still obeying Hooke's law?

Use the direct proportional relationship between force and extension.

What happens when a spring is stretched beyond its elastic limit?

It becomes permanently deformed and does not return to its original length.

How can students measure the mean speed of cars passing their school?

Measure a known distance along the road, time each car travelling that distance and calculate speed using distance ÷ time. Repeat for several cars and calculate a mean.

How do you calculate mean speed?

Mean speed = total distance travelled ÷ total time taken.

What does a steeper velocity-time graph mean?

Greater acceleration.

How do you calculate acceleration?

Acceleration = change in velocity ÷ time taken.

Why might two toy cars with the same mass take different times to reach their top speeds?

They may experience different resultant forces, for example due to different motor forces or resistive forces.

How do you calculate current using potential difference and resistance?

Current = potential difference ÷ resistance.

A 6.0 V supply is connected to two 5.0 Ω resistors in series. Calculate the current.

Total resistance = 5.0 + 5.0 = 10.0 Ω. Current = 6.0 ÷ 10.0 = 0.60 A.

How do you calculate potential difference across a resistor?

Potential difference = current × resistance.

What happens to the potential difference across identical resistors connected in series?

The supply potential difference is shared between them equally.

What is the charge on the nucleus of an atom?

Positive.

What is the current in a series circuit?

The current is the same at every point in the circuit.

What measuring equipment is used to measure the distance of a swimming pool length?

A trundle wheel.

What measuring equipment is used to measure the time taken to swim a pool length?

A stopwatch.

What happens to the temperature of a substance during melting?

It stays constant while energy is supplied, because the energy is used to overcome forces between particles.

What is a current-potential difference graph for a filament lamp like?

Non-linear. Its resistance increases as it gets hotter.

How do you connect an ammeter and voltmeter to measure current and potential difference across a thermistor?

Connect the ammeter in series and the voltmeter in parallel across the thermistor.

An object has a mass of 37.5 kg and a volume of 0.15 m³. Calculate its density.

37.5 ÷ 0.15 = 250 kg/m³.

How do you calculate power?

Power = energy transferred ÷ time.