Physics

The velocity of a proton (${}^1_1\mathrm{H}$) is twice the velocity of an alpha particle (${}^4_2\mathrm{He}$). The proton has a de Broglie wavelength of $\lambda$.

What is the de Broglie wavelength of the alpha particle?
A. $\frac{\lambda}{8}$
B. $\frac{\lambda}{2}$ C. D.

A coil of wire is rotating about a vertical axis in a magnetic field that is directed $45^\circ$ below the horizontal:

Which set of changes will result in the largest reading on the voltmeter?
A. Double $r$ and halve $l$.
B. Increase both $l$ and $r$ by $50\%$.
C. Rotate the magnetic field to vertical and double $r$.
D. Rotate the magnetic field to horizontal and double $l$.

A uniform magnetic field is directed into the page. A conductor $PQ$ rotates about the end $P$ at a constant rate.

Which graph shows the emf induced between the ends of the conductor, $P$ and $Q$, as it rotates one revolution from the position shown?

Two stars, A and B, are equally bright as seen from the Earth. Stars A and B are $10$ and $15$ parsecs away from Earth respectively. One parsec $=3.26$ light years.

Which of the following statements about the luminosities of stars A and B ($L_A$ and $L_B$) are correct?
A. $L_A=\frac{3}{2}L_B$
B. $L_A=\frac{2}{3}L_B$
C. $L_A=\frac{4}{9}L_B$
D. $L_A=\frac{9}{4}L_B$

The graph shows the relationship between the maximum kinetic energy of emitted photoelectrons and the incident photon energy for four different metal surfaces.

Light of frequency $7 \times 10^{14}\,\mathrm{Hz}$ is incident on the metals.

From which metals are photoelectrons emitted?
A. K, Li only
B. Mg, Ag only
C. All of the metals
D. None of the metals

The diagram shows a type of particle accelerator called a cyclotron.

Cyclotrons accelerate charged particles, following the path as shown.

An electric field acts on a charged particle as it moves through the gap between the dees. A strong magnetic field is also in place.

Once a charged particle has the required velocity, it exits the accelerator towards a target.

Which of the following is true about a charged particle in a cyclotron?
A. It increases speed while inside the dees.
B. It only accelerates while between the dees.
C. It undergoes acceleration inside and between the dees.
D. It slows down inside the dees and speeds up between the dees.

Three wires carry currents, as shown in the following scale diagram.

How many of the wires experience a net force to the left?
A. $0$
B. $1$
C. $2$
D. $3$

The diagram shows a magnet moving towards a coil $X$.

This action causes a current to be induced in the coil.

Which situation will induce a current in coil $X$ that is in the same direction as the current induced by the movement of the magnet?

In a vacuum chamber there is a uniform electric field and a uniform magnetic field.

A proton having a velocity, $v$, enters the chamber. Its velocity remains unchanged as it travels through the chamber.

A second proton having a velocity, $2v$, in the same direction as the first proton, then enters the chamber at the same point as the first proton.

In the chamber, the acceleration of the second proton
A. is zero.
B. is constant in magnitude and direction.
C. changes in both magnitude and direction.
D. is constant in magnitude, but not direction.

The energy-level diagram for a particular element is shown below.

Which of the following is inconsistent with the wavelength of a photon emitted from an atom of the element during an electron transition?
A. $48.3\ \mathrm{nm}$
B. $66.4\ \mathrm{nm}$
C. $72.6\ \mathrm{nm}$
D. $169.0\ \mathrm{nm}$

Jo is in the centre of a train carriage travelling close to the speed of light to the right. Lamps F and B, located at the front and back of the train respectively, are switched on simultaneously as Jo passes an observer Bo, who is on the platform equidistant from the lamps when the light is emitted.

According to Bo, which of the following statements is correct in terms of the perceived arrival times of the flashes of light?
A. The lights turn on simultaneously for Jo.
B. The lights turn on simultaneously for Bo.
C. The light at the back turns on before the light at the front for Jo.
D. The light at the front turns on before the light at the back for Bo.

Three identical atomic clocks are made so that they tick at precisely the same rate. One is kept in a laboratory, $X$, on Earth’s equator. Another is placed on board a satellite, $Y$, in a circular orbit with a period of 12 hours. A third is placed in a satellite, $Z$, that is in a geostationary orbit. The satellites orbit Earth in the equatorial plane.

Assume that the satellites are inertial frames of reference and the clocks are affected ONLY by the predictions of special relativity.

Which statement correctly compares the rates at which the clocks tick, as determined by an observer at $X$, when the satellites are in the positions shown in the diagram?
A. The clock at $Y$ ticks faster than either the clock at $X$ or the clock at $Z$.
B. The clock at $Y$ ticks slower than either the clock at $X$ or the clock at $Z$.
C. The clocks tick at different rates, with $X$ being the fastest and $Y$ being the slowest.
D. The clocks tick at different rates, with $Z$ being the slowest and $X$ being the fastest.

Artificial satellites monitor weather conditions on Earth and are used for surveillance and communications. Such satellites may be placed in a geostationary orbit.
Explain what happens to the speed of a satellite when it moves to a lower orbit.

Artificial satellites monitor weather conditions on Earth and are used for surveillance and communications. Such satellites may be placed in a geostationary orbit.

(a) Identify TWO features of a geostationary orbit.

The following graph, based on the data gathered by Hubble, shows the relationship between the recessional velocity of galaxies and their distance from Earth.
Describe the significance of the graph to our understanding of the universe.

The following graph, based on the data gathered by Hubble, shows the relationship between the recessional velocity of galaxies and their distance from Earth.
How were the recessional velocities of galaxies determined?

Development of models of the atom has resulted from both experimental investigations and hypotheses based on theoretical considerations.
Explain how de Broglie’s hypothesis regarding the nature of electrons addressed limitations in the Bohr–Rutherford model of the atom.

An absorption spectrum resulting from the passage of visible light from a star’s surface through its hydrogen atmosphere is shown. Absorption lines are labelled W to Z in the diagram.

Absorption line $W$ originates from an electron transition between the second and sixth energy levels. Use

to calculate the frequency of light absorbed to produce absorption line $W$.

An absorption spectrum resulting from the passage of visible light from a star’s surface through its hydrogen atmosphere is shown. Absorption lines are labelled W to Z in the diagram.
Determine the surface temperature of the star.

An absorption spectrum resulting from the passage of visible light from a star’s surface through its hydrogen atmosphere is shown. Absorption lines are labelled W to Z in the diagram.
Explain the physical processes that produce an absorption spectrum.

The mathematical model below shows the relationship between the orbital radius of a satellite and its period.

(b) A planet with five moons is discovered. The following graph is produced from observations of the orbital radius of the moons and their orbital periods, measured in Earth days.

Use the graph to calculate the mass of the planet.

The mathematical model below shows the relationship between the orbital radius of a satellite and its period.

(a) By considering gravitational force, show how this model can be derived.

Muons are unstable particles produced when cosmic rays strike atoms high in the atmosphere. The muons travel downward, perpendicular to Earth’s surface, at almost the speed of light.

Classical physics predicts that these muons will decay before they have time to reach Earth’s surface.

Explain qualitatively why these muons can reach Earth’s surface, regardless of whether their motion is considered from either the muon’s frame of reference or the Earth’s frame of reference.

The simplified model below shows the reactants and products of a proton–antiproton reaction which produces three particles called pions, each having a different charge.

There are no other products in this process, which involves only the rearrangement of quarks. No electromagnetic radiation is produced. Assume that the initial kinetic energy of the proton and antiproton is negligible.

Protons consist of two up quarks ($u$) and a down quark ($d$). Antiprotons consist of two up antiquarks ($\bar{u}$) and a down antiquark ($\bar{d}$). Each of the pions consists of two quarks.

The following tables provide information about hadrons and quarks.

Table 1: Hadron information

Table 2: Quark charges

(b) The energy released in the reaction is shared equally between the pions. Calculate the energy released per pion in this reaction.