Physics

Which of the following provides evidence for the model of light proposed by Huygens?
A. Emission spectra
B. Diffraction of light
C. Black-body radiation
D. The photoelectric effect

An object is moving in a horizontal circle on a string with a constant angular velocity $\omega$. The tension in the string, which is approximately horizontal, is $F$. If $\omega$ is doubled while all the other quantities are kept constant, what will the tension in the string become?
A. $4F$
B. $2F$
C. $F/2$
D. $F/4$

Which of the following is a fundamental particle in the Standard Model of matter?
A. Hadron
B. Neutron
C. Photon
D. Proton

If an astronaut orbiting the Earth near its surface were to stand on a set of bathroom scales, why would there be a reading of zero?
A. The astronaut’s mass becomes zero.
B. The strength of the gravitational field is zero.
C. The pull of the Earth is balanced by the pull of the Moon.
D. The astronaut falls towards the Earth at the same rate as the space capsule.

An object is executing uniform circular motion, as shown in the figure below.

At position P, which of the following shows the directions of instantaneous velocity and acceleration?
A. $\vec{v}$ downward and $\vec{a}$ downward.
B. $\vec{v}$ downward and $\vec{a}$ upward.
C. $\vec{v}$ downward and $\vec{a}$ to the right.
D. $\vec{v}$ downward and $\vec{a}$ to the left.

A conducting coil is mounted on an axle and placed in a uniform magnetic field. The diagram shows different ways of connecting the coil to a power source.

Which setup allows the conducting coil to rotate continuously?

Iodine–131 is a radioisotope used in nuclear medicine. It has a half-life of 8 hours and eventually becomes a stable isotope Xenon-131 according to the following equation:

24.0 mg of Iodine–131 is injected in the body of a patient.

How many milligrams of Xenon-131, produced as a result of this reaction, is present in the body after 16 hours?
A. 6.0
B. 12.0
C. 18.0
D. 24.0

A star cluster is a group of stars that form at the same time. Hertzsprung–Russell diagrams for three star clusters, $X$, $Y$ and $Z$ are shown.

Which row of the table correctly shows the three star clusters from youngest to oldest?
A. Youngest $Y$, then $X$, then oldest $Z$
B. Youngest $Y$, then $Z$, then oldest $X$
C. Youngest $Z$, then $X$, then oldest $Y$
D. Youngest $Z$, then $Y$, then oldest $X$

A horizontal metal cylinder PQ, perpendicular to the page, moves down between two solenoids, as shown below:

Which of the following correctly show the direction of the magnetic field between the solenoids and the charge at P?

The photoelectric effect is mathematically modelled by the following relationship:

In this model, the symbol $\phi$ represents the amount of energy
A. supplied by a photon to an electron.
B. retained by an electron after being hit.
C. required to release an electron from a material.
D. left over after a collision of a photon with an electron.

A radioactive isotope decays by alpha and beta particle emission. Over a number of decays, the nucleon number decreases by 4 while the proton number is unchanged.

How many alpha and beta particles have been emitted?
A. 2 alpha particles and 1 beta particle
B. 1 alpha particle and 2 beta particles
C. 1 alpha particle and 1 beta particle
D. 2 alpha particles and 2 beta particles

A pure sample of polonium-210 undergoes alpha emission to produce the stable isotope lead-206.

The half-life of polonium-210 is 138 days.

At the end of 276 days, what is the ratio of polonium-210 atoms to lead-206 atoms in the sample?
A. $1:4$
B. $1:3$
C. $1:2$
D. $1:1$

An ideal transformer produces an output of $6\ \mathrm{V}$ when an input of $240\ \mathrm{V}$ is applied.

What change would be needed to produce an output of $12\ \mathrm{V}$, using the same input voltage?
A. Increase the number of turns on the primary coil
B. Decrease the number of turns on the primary coil
C. Increase the resistance connected to the secondary coil
D. Decrease the resistance connected to the secondary coil

Two students are discussing the advantages of magnetic brakes.

Student A says that because the magnetic force is proportional to velocity they provide a smoother braking action.

Student B says that because magnetic fields do no work, the brakes produce no heat.

Which of the students, if any, is/are correct?
A. Student A only
B. Student B only
C. Both student A and student B
D. Neither student A nor student B

Object $P$ is dropped from rest, and object $Q$ is launched horizontally from the same height.

Which option correctly compares the projectile motion of $P$ and $Q$?
A. The acceleration of $P$ is less than the acceleration of $Q$.
B. The final velocity of $Q$ is greater than the final velocity of $P$.
C. The time of flight of $Q$ is greater than the time of flight of $P$.
D. The initial vertical velocity of $P$ is less than the initial vertical velocity of $Q$.

Control rods and moderators play a key role in controlling the rate of fission in nuclear reactors.

Which row of the table correctly shows how this is achieved?

A rod carrying a current, $I$, placed in a uniform magnetic field as shown, experiences a force $F$.

How many degrees must the rod be rotated clockwise so that it experiences a force $\dfrac{F}{2}$?
A. $30^\circ$
B. $45^\circ$
C. $60^\circ$
D. $90^\circ$

This is a Hertzsprung–Russell (H–R) diagram showing many star plots. The axes are not labelled.

Which of the following statements is true of the luminosity and temperature of stars A and B?
A. The luminosity of star A is lower while the temperature of star B is higher.
B. The luminosity of star A is lower while the temperature of star B is lower.
C. The luminosity of star A is higher while the temperature of star B is higher.
D. The luminosity of star A is higher while the temperature of star B is lower.

At what angle, $\theta$, should two polaroid sheets be placed to reduce the intensity by ninety percent?
A. $\theta=\cos^{-1}\sqrt{0.8}$
B. $\theta=\cos^{-1}\sqrt{0.2}$
C. $\theta=\cos^{-1}\sqrt{0.9}$
D. $\theta=\cos^{-1}\sqrt{0.1}$

A rod has a length, $L_0$, when measured in its own frame of reference.

The rod travels past a stationary observer at speed, $v$, as shown in the diagram.

Which option represents the relationship between the speed of the rod, $v$, and the length of the rod as measured by the stationary observer?
A. $W$
B. $X$
C. $Y$
D. $Z$

The diagram shows a discharge tube used by Thomson to investigate cathode rays. When the connections are made to a high-voltage power supply, cathode rays are produced at C and accelerated across AB and through parallel plates P and Q, connected to a second power supply, with P positively charged. The rays then hit the centre of the fluorescent screen when a magnetic field is positioned in the XY direction between plates P and Q.

Which row of the table shows the aim of this experiment and the correct direction of the applied magnetic field?

aThe diagram shows two identical satellites, $A$ and $B$, orbiting a planet.

Which row in the table correctly compares the potential energy, $U$, and kinetic energy, $K$, of the satellites?
A. $U_A > U_B$; $K_A < K_B$
B. $U_A < U_B$; $K_A > K_B$
C. $U_A > U_B$; $K_A > K_B$
D. $U_A < U_B$; $K_A < K_B$

Two satellites orbit a planet. One of the satellites has an orbital radius of $2.3\times10^{6}\ \mathrm{m}$ and a period of $7.6\times10^{4}\ \mathrm{s}$. The other satellite has an orbital period of $1.3\times10^{5}\ \mathrm{s}$. What is the orbital radius of this second satellite?
A. $1.3\times10^{6}\ \mathrm{m}$
B. $3.3\times10^{6}\ \mathrm{m}$
C. $3.9\times10^{6}\ \mathrm{m}$
D. $5.1\times10^{6}\ \mathrm{m}$