Physics Paper 2 November 2023

1. Ano resultant external force acts on the system.
2. Bno internal forces act between the particles of the system.
3. Cthe total kinetic energy of the system is conserved as well.
4. Devery particle in the system moves with the same velocity.

Answer this when you sit the paper.

Answer this when you sit the paper.

1. Areduces the total change of momentum of the head, so a smaller impulse has to act on the neck.
2. Baccelerates the head forwards with the torso, so head and shoulders move together and the neck bends far less.
3. Ckeeps the head above the shoulders, so the passenger's centre of gravity stays over the seat throughout.
4. Dholds the head stationary while the torso is pushed forwards, so the neck takes the load gradually.

1. AThe speed increases steadily while the direction of the velocity is unchanged, so the body follows a straight line with uniform acceleration.
2. BThe speed stays constant while the direction of the velocity changes continuously, so the body follows a circle with its acceleration directed to the centre.
3. CBoth the speed and the direction of the velocity change continuously, so the body follows an outward spiral whose radius grows steadily as it goes.
4. DThe speed falls steadily while the direction of the velocity changes, so the body follows a circle of steadily decreasing radius.

1. Aconstant in magnitude and always directed towards the point of maximum displacement.
2. Bdirectly proportional to its displacement from a fixed point and always directed towards that point.
3. Cdirectly proportional to its displacement from a fixed point and always directed away from that point.
4. Dinversely proportional to its displacement from a fixed point and always directed towards that point.

Answer this when you sit the paper.

Answer this when you sit the paper.

1. AThe displacement is large enough to take the springs past their elastic limit before they are released.
2. BThe two springs have different spring constants, so their restoring forces do not simply add.
3. CThe trolley is much lighter than the springs, so most of the oscillating mass is in the springs.
4. DThe track and the wheels are frictionless, so the oscillation is undamped and the amplitude does not fall.

1. Aradio waves flip the spin of hydrogen nuclei held in a strong magnetic field, and the signal the nuclei re-emit as they relax is mapped point by point.
2. Ba pulse of ultrasound is sent into the body and the depth of each boundary is found from the time its echo takes to come back.
3. Can X-ray beam and its detectors rotate around the patient, and a computer reconstructs the slice from the attenuation measured along many directions.
4. Dgamma rays emitted by a tracer taken into the patient are picked up by a ring of counters that record where each decay took place.

1. Aone coulomb of charge for each joule of energy stored in it.
2. Bone volt of potential difference for each coulomb of charge on its plates.
3. Cone coulomb of charge for each volt of potential difference across it.
4. Done joule of energy for each coulomb of charge on its plates.

Answer this when you sit the paper.

Answer this when you sit the paper.

1. AThey each end at 10 V, because disconnecting the supply fixes the potential difference on the plates.
2. BThey share the original 60 uC between them and both end at the same potential difference of 2.9 V.
3. CThey each keep 60 uC, so the total charge in the circuit rises to 120 uC at a shared p.d. of 2.9 V.
4. DThey share the original 60 uC, and the smaller capacitor ends at the higher potential difference.

Tap to enlarge

1. AOnly when the two switches are set to the same number, that is (0, 0) or (1, 1).
2. BFor every setting except (0, 0), so that the circuit behaves as an OR gate.
3. COnly when the two switches are set to different numbers, that is (0, 1) or (1, 0).
4. DOnly for the setting (1, 1), so that the circuit behaves as an AND gate.

1. A3
2. B4
3. C5
4. D6

1. Athe product of the pressure and the volume of the fluid stays constant at a fixed temperature.
2. Bthe mass of fluid crossing each cross-section per second falls wherever the pipe narrows.
3. Cthe sum of the pressure and the kinetic and potential energies per unit volume stays constant.
4. Dthe pressure rises wherever the speed of the fluid rises, provided the height is unchanged.

1. Athe pressure term measures the heat given out by the fluid, which balances the kinetic energy it gains.
2. Bit shows that the mass of fluid entering a pipe each second is equal to the mass of fluid that leaves that pipe each second.
3. Cthe density of the fluid is unchanged, so the fluid can neither gain nor lose gravitational potential energy.
4. Deach of its three terms is an energy per unit volume of fluid, and no energy leaves a non-viscous fluid in steady flow.

1. Aits molecules are not held at fixed sites and its intermolecular forces are weaker, so the same energy pushes them further apart.
2. Bits molecules are already touching the container, so the container's own expansion is added to that of the liquid.
3. Cits molecules vibrate about fixed sites while a solid's molecules move freely, so its vibrations have the larger amplitude.
4. Dits molecules are heavier, so each one carries more kinetic energy at a given temperature and needs more room.

1. Ato raise the mean kinetic energy of all of the molecules, which is what lets the fastest of them break through the surface of the liquid.
2. Bto raise the pressure of the liquid until it becomes equal to the pressure of the atmosphere above the surface.
3. Cto do work against the intermolecular forces holding the molecules in the liquid, and to push back the atmosphere as vapour forms.
4. Dto increase the specific heat capacity of the liquid, so that its temperature can no longer rise while it boils.

1. Athe lid keeps air away from the food, so oxidation of the food no longer takes energy away from the heating.
2. Bthe trapped vapour lowers the pressure inside, and a lower pressure lets water boil at a temperature well above 100 degrees C.
3. Cthe trapped vapour raises the pressure inside, and the boiling point rises with pressure, so the food cooks at a higher temperature.
4. Dthe lid reflects the infrared radiation from the flame back into the food, adding to the heat conducted through the base.

1. AEmission: bright lines on a dark background from excited atoms falling to lower levels. Absorption: dark lines on a continuous bright background where photons have been removed.
2. BEmission: dark lines on a continuous bright background where photons have been removed. Absorption: bright lines on a dark background from excited atoms falling to lower levels.
3. CEmission: a continuous band of all colours given out by a hot solid. Absorption: bright lines on a dark background given out by a cool low-pressure gas.
4. DEmission: bright lines whose wavelengths depend on the temperature of the gas. Absorption: dark lines whose wavelengths depend on the pressure of the gas.

1. Athe electrons in the atom carry enough momentum to turn a fast alpha particle back along its path.
2. Bthe gold foil used was many atoms thick, so each alpha particle met a great many nuclei in turn.
3. Cthe atom is a sphere of positive charge in which the electrons sit embedded at regular intervals.
4. Dthe positive charge and nearly all the mass of an atom are concentrated in a very small, dense nucleus.

1. Athe product $\lambda t_{1/2}$ is equal to $\ln 2$, about 0.693.
2. Bthe ratio $\lambda / t_{1/2}$ is equal to $\ln 2$, about 0.693.
3. Cthe product $\lambda t_{1/2}$ is equal to 1 exactly.
4. Dthe product $\lambda t_{1/2}$ is equal to 2 exactly.

Answer this when you sit the paper.

1. Athe isotopes present have half-lives of a few seconds, so almost all of them decay before the food is swallowed.
2. Bonly a trace of the isotope is present, so the activity and the dose rate to any tissue are both very small.
3. Cthe isotopes present decay by emitting gamma rays, which pass straight through the body without interacting.
4. Dthe digestive system converts the isotopes into stable nuclides before they can reach any of the body tissues.

1. AAM varies the carrier's frequency with the signal and leaves its amplitude fixed, while FM varies its amplitude and leaves its frequency fixed.
2. BAM varies the carrier's amplitude with the signal while FM varies its wavelength, and both leave the speed of the carrier unchanged.
3. CAM and FM both vary the carrier's amplitude, but FM also shifts the carrier onto a higher frequency band before transmission.
4. DAM varies the carrier's amplitude with the signal and leaves its frequency fixed, while FM varies its frequency and leaves its amplitude fixed.

1. Anoise picked up along the route is amplified with the signal at every repeater and cannot be separated from it.
2. Bit varies in steps rather than continuously, so the fine detail of the original information is lost on the way.
3. Cit can only be sent along a wire, since an analogue waveform cannot be used to modulate a carrier wave.
4. Dit has to be sampled many times each second, which sets a limit on the highest frequency the system can carry.

Answer this when you sit the paper.

Tap to enlarge

1. A2 V, 4 V, 6 V, 3 V, 4 V, 2 V and 1 V
2. B2 V, 7 V, 3 V, 4 V and 1 V
3. C2 V, 6 V, 4 V, 3 V and 1 V
4. D2 V, 6 V, 3 V, 4 V and 1 V

1. A0100, 0110, 1100, 0010, 1000
2. B0001, 0101, 0010, 0011, 0000
3. C0010, 0011, 0110, 0100, 0001
4. D0010, 0110, 0011, 0100, 0001

1. Aincreasing the sampling frequency, so that the steps are narrower and follow the original curve more closely.
2. Bdecreasing the sampling frequency, so that fewer steps are needed and each one of them lasts a good deal longer.
3. Creducing the number of bits per sample, so that each level is recorded with a shorter binary word.
4. Dincreasing the amplitude of the carrier wave, so that the steps in the recovered signal are taller.