Physics SL

Question 1

It takes an object two seconds to move from point A to point B along the path shown in the diagram.

What is the average speed and the magnitude of the average velocity of the object?

Question 2

The diagram shows two masses, M and m that are connected by a string through a pulley, where M > m. The mass of the string and the friction between the string and the pulley are negligible.

What is the acceleration of mass M?

1. \frac{g(M+m)}{M}
2. \frac{g(M-m)}{M}
3. \frac{g(M+m)}{M-m}
4. \frac{g(M-m)}{M+m}

Question 3

A submarine moves through a lake with a speed of 8.0 m s^{-1}. The output power of the submarine’s engine is 2.0 MW. What is the resistive force that acts on the submarine?

1. 25 kN
2. 160 kN
3. 250 kN
4. 1600 kN

Question 4

According to Newton’s third law of motion, what is an action-reaction force pair when a person is sitting on a chair?

Question 5

A stone of mass M is attached to a string and moves in a horizontal circle or radius R. It takes the stone 2 seconds to complete one revolution.

What is the work done by the centripetal force during 1 second of the stone’s motion?

1. Zero
2. 2\pi^{2}R^{2}M
3. \pi^{3}R^{2}M
4. 2\pi^{3}R^{2}M

Question 6

A block slides down a frictionless ramp from a vertical height of x. 

The block arrives at the bottom of the ramp at speed v and it eventually comes to rest on a rough horizontal surface after travelling through distance s. The coefficient of dynamic friction between the block and the surface is \mu. What is s?

1. \frac{x}{\mu}
2. \frac{\mu}{x}
3. \frac{v^{2}}{\mu g}
4. \frac{2v^{2}}{\mu g}

Question 7

A thermally isolated tube contains only water molecules. The tube is cooled to the freezing point of water. While the water is changing phase:

1. its temperature decreases.
2. the mean potential energy of the water molecules decreases.
3. the mean kinetic energy of the water molecules decreases.
4. the mean thermal energy of the water molecules decreases.

Question 8

The albedo of ice that covers a lake during winter is 0.75. This means that:

1. the ice reflects 75 % of the radiation that is incident on its surface.
2. the ice reflects 25 % of the radiation that is incident on its surface.
3. 75 % of the radiation that is emitted by the ice falls into the ultraviolet region of the electromagnetic spectrum. 
4. 25 % of the radiation that is emitted by the ice falls into the ultraviolet region of the electromagnetic spectrum.

Question 9

The internal resistance of a 32 V battery is 4.0\: \Omega. A lightbulb has three times the resistance than the internal resistance of the battery. The lightbulb is connected to the battery. Which of the following statements is incorrect for the circuit?

1. The power dissipated in the lightbulb is 48 W.
2. The potential difference across the lightbulb is 32 V.
3. The total resistance in the circuit is 16\: \Omega.
4. The current in the battery is 2.0 A.

Question 10

The specific heat capacity of a substance in the solid state is c and the specific latent heat of fusion of the substance is L. When 5000 J of energy is supplied to m kg of this substance in the solid state, the temperature of the substance increases by 50 K. When 20000 J of energy is supplied to \frac{m}{2} kg of this substance in the solid state at its melting point, the substance completely melts without a change in its temperature. What is the ratio \frac{c}{L}?

1. 0.010 K
2. 0.0025 K
3. 0.010 K^{-1}
4. 0.0025 K^{-1}

Question 11

Containers C and D contain the same ideal gas. The gas in container C is at a temperature of 500 K. The pressure in C is a third of the pressure in D. The volume of C is five times the volume of D. There are four times as many molecules in D than in C. What is the temperature in D?

1. -198 ^{o}C
2. 75 ^{o}C
3. 348 ^{o}C
4. 1200 ^{o}C

Question 12

Two resistors, X and Y, are connected as shown on the diagram. The ammeter and the voltmeter are ideal and the cell has negligible internal resistance.

What happens to the ammeter reading and the voltmeter reading when the resistance of resistor Y is halved?

Question 13

A mass-spring system oscillates with simple harmonic motion (SHM). What is true about the restoring force that acts on the system?

1. It is proportional to the amplitude of the oscillations.
2. It is pointing in the opposite direction to the displacement for half of the period. 
3. It is proportional to the displacement from the equilibrium position.
4. It is pointing away from the equilibrium position.

Question 14

In a double-slit experiment monochromatic violet light is incident on two slits that are located at a distance d from a screen. The separation of the slits is s. The distance between consecutive dark fringes in the interference pattern that forms on the screen is a. 

The experiment can be modified in the following ways:

I. Changing violet light to yellow light.

II. Decreasing d.

III. Decreasing s.

Which of these modifications will cause a to increase?

1. I and II only
2. I and III only
3. II and III only
4. I, II and III

Question 15

The displacement of a particle in a traveling wave varies with time as shown on the graph. What are the amplitude and the frequency of the particle’s motion?

Question 16

A third-harmonic standing sound wave is formed in a pipe that is open at one end and closed at the other end. The length of the pipe is 1.2 m. Point X is located 20 cm from the closed end of the pipe and point Y is located 60 cm from the closed end of the pipe. What is the phase difference between the motion of a particle at point X and the motion of a particle at point Y?

1. 0
2. \frac{\pi}{4}
3. \frac{\pi}{2}
4. \pi

Question 17

The gravitational force acting between two objects is F. The mass of each object is m and the distance between the objects is x. What will be the gravitational force acting between two objects that each have a mass of 2m when the distance between them is 2x?

1. \frac{F}{4}
2. \frac{F}{2}
3. F
4. 2F

Question 18

A proton, moving with initial velocity v, enters an electric field between two parallel, horizontal plates near the surface of the Earth. The velocity of the proton does not change as it moves through the electric field. What is the direction and the best estimate for the magnitude of the electric field between the plates?

Question 19

A proton moves in an electric field. Which of the following paths requires the electric field to do the most work?

Question 20

Moon A has mass M, radius R and the gravitational field strength on the surface of Moon A is g. Moon B has mass 3M and the gravitational field strength on its surface is \frac{g}{4}.

What is the diameter of Moon B?

1. 2\sqrt{3}R
2. 4\sqrt{3}R
3. 12R
4. 24R

Question 21

The initial number of undecayed nuclides in a radioactive sample is N. Which graph correctly shows how N varies with time?

Question 22

The diagram shows a simple model of the four energy levels in an atom.

What is the best estimate for the smallest and for the largest frequency in the absorption spectrum of the atom?

Question 23

Under what temperature and density conditions does fusion take place in stars?

Question 24

The initial activity of a radioactive sample is 160 Bq and the background activity at this location is 25% of the initial activity of the sample. The half-life of the radioactive nuclide is 7 hours.

What is the activity detected at the location of the sample after 21 hours?

1. 25 Bq
2. 40 Bq
3. 60 Bq
4. 80 Bq

Question 25

A moderator and control rods are two key parts of a nuclear power station. What is true about the atoms in a moderator and the atoms in control rods?

1. Both are good absorbers of neutrons.
2. Both are poor absorbers of neutrons.
3. Moderator atoms are good absorbers of neutrons, control rod atoms are poor absorbers of neutrons.
4. Moderator atoms are poor absorbers of neutrons, control rod atoms are good absorbers of neutrons.

Question 1

A student carries out an investigation to determine the relationship between the tension T in a wire of fixed length and the frequency f of the fundamental vibration of a standing wave on the wire.

For T = 10 N, the student measures the frequency five times and records the following values:

The student then carries out two different calculations for the mean value of f and obtains 176.2 Hz and 182 Hz.

(a)   Comment on these mean values.

[2]

The graph of f against T is plotted.

(b)   The uncertainty in T is \pm 5\% and the uncertainty in f is \pm 20 Hz.

(i)   Draw error bars for the data point where T = 40 N.

[2]

(ii)   Calculate the largest percentage uncertainty in f for these data values.

[2]

The student hypothesizes that the relationship between T and f can be described as f = A\sqrt{T} where A is a constant. 

(c)   

(i)   Find the fundamental SI unit for A.

[2]

(ii)   Write down a pair of quantities that the student can plot in order to test the hypothesis.

[1]

(iii)   Using the data point where T = 10 N, determine the uncertainty in A.

[3]

Question 2

A student carries out an experiment to find the internal resistance r and the electromotive force (emf) \varepsilon of a cell. The student uses a circuit to measure the terminal potential difference V and current I.

The uncertainty in the measurement of each value of I is \pm 2 mA and the uncertainty in the measurement of each value of V is \pm 0.04 V.

The data collected by the student is plotted on a graph.

(a)

(i)   State and explain why no horizontal error bars are shown for the data points.

[2]

(ii)   Draw the line of best fit for the data.

[1]

(b)   For this investigation V = -Ir + \varepsilon.

        Using the graph

(i)   find the internal resistance of the cell. Give your answer together with an appropriate unit. 

[3]

(ii)   determine the emf of the cell along with its uncertainty and give your answer in an appropriate format.

[2]