Physics HL

PaperPlainz Accelerator

 Level 1

Paper 1
Paper 2

Paper 1

Question 1

Which of the following are two vector quantities?

  1. Speed, Mass
  2. Speed, Force
  3. Velocity, Mass
  4. Force, Velocity
Answer

D.

Video Solution

Done Under 90

Question 2

A graph shows how the velocity of an object varies with time. What does the gradient of the graph represent?

  1. The displacement of the object
  2. The acceleration of the object
  3. The momentum of the object
  4. It does not represent a physical quantity
Answer

B.

Video Solution

Done Under 90

Question 3

Newton’s second law of motion states that:

  1. The net force acting on a body is equal to the product of its mass and velocity.
  2. When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.
  3. The net force acting on a body is proportional to the momentum of the body.
  4. The rate of change of momentum of a body is equal to the net force acting on the body.
Answer

D.

Video Solution

Done Under 90

Question 4

A car of mass m is traveling along a horizontal road at constant speed. The total resistive force acting on the car is F and the power of the car’s engine is P. What is the speed of the car?

  1. mP
  2. FP
  3. \frac{P}{m}
  4. \frac{P}{F}
Answer

D.

Video Solution

Done Under 90

Question 5

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?

Average speed

Magnitude of average velocity
A. 4 + 2 \pi m s^{-1} 6 m s^{-1}
B. 4 + 2 \pi m s^{-1} 4 + \pi m s^{-1}
C. 4 + \pi m s^{-1} 6 m s^{-1}
D. 4 + \pi m s^{-1} 4 + \pi m s^{-1}
Answer

C.

Video Solution

Done Under 90

Question 6

A firework rocket is launched vertically upwards and it explodes when it reaches a height of 50 m. What is true about the kinetic energy and the momentum of the system when compared right before and right after the explosion?

Kinetic energy

Momentum
A. Conserved Conserved
B. Increased Increased
C. Increased Conserved
D. Conserved Increased
Answer

C.

Video Solution

Done Under 90

Question 7

Boxes A and B are pushed along a surface by a 20 N force. The mass of box A is 1.5 kg and the mass of box B is 0.50 kg. The boxes travel at constant speed. 

What is the resultant force that acts on box B?

  1. 20 N
  2. 15 N
  3. 5.0 N
  4. 0
Answer

D.

Video Solution

Done Under 90

Question 8

A temperature of 58 ^{o}C is equal to:

  1. -215 K
  2. 215 K
  3. -331 K
  4. 331 K
Answer

D.

Video Solution

Done Under 90

Question 9

A monatomic real gas can behave very similarly to an ideal gas under certain conditions. Which of the following is one of these conditions?

  1. Low pressure
  2. Low temperature
  3. High pressure
  4. High density
Answer

A.

Video Solution

Done Under 90

Question 10

When a transverse wave travels through a medium, which of the following is true about the direction of propagation and the energy transfer of the wave in relation to the displacement of the medium?

Direction of propagation

Direction of energy transfer
A. Perpendicular Parallel
B. Parallel Parallel
C. Parallel Perpendicular
D. Perpendicular Perpendicular
Answer

D.

Video Solution

Done Under 90

Question 11

Two pulses travel towards each other as shown on the diagram. 

Which one of the following diagrams shows a possible configuration when the two pulses meet?

Answer

C.

Video Solution

Done Under 90

Question 12

What is true about the magnitude of the acceleration of an object that is moving with simple harmonic motion (SHM)? 

  1. It is maximum when the magnitude of the displacement is at its maximum.
  2. It is maximum when speed is at its maximum.
  3. It is constant.
  4. It is never zero.
Answer

A.

Video Solution

Done Under 90

Question 13

Which of the following lists electromagnetic waves in increasing order of frequency?

  1. Red light, radio waves, microwaves
  2. Red light, microwaves, radio waves
  3. Microwaves, radio waves, red light
  4. Radio waves, microwaves, red light
Answer

D.

Video Solution

Done Under 90

Question 14

One electronvolt is equivalent to:

  1. 1.6 \times 10^{-19} N
  2. 1.6 \times 10^{-19} W
  3. 1.6 \times 10^{-19} V
  4. 1.6 \times 10^{-19} J
Answer

D.

Video Solution

Done Under 90

Question 15

The power supplied by a battery per unit current from the battery is a definition of:

  1. Potential difference
  2. Electromotive force
  3. Internal resistance
  4. Ohm’s law
Answer

B.

Video Solution

Done Under 90

Question 16

A student wants to connect an ammeter and a voltmeter to measure the current through and the potential difference across a resistor. How should the ammeter and the voltmeter be connected to the resistor?

Ammeter

Voltmeter
A. Series Parallel
B. Parallel Series
C. Series Series
D. Parallel Parallel
Answer

A.

Video Solution

Done Under 90

Question 17

What is true about a secondary cell’s ability to be recharged and the energy conversion when the cell is discharging?

Ability to be recharged

Energy conversion during discharge
A. Can be recharged Electrical energy to chemical energy
B. Cannot be recharged Electrical energy to chemical energy
C. Can be recharged Chemical energy to electrical energy
D. Cannot be recharged Chemical energy to electrical energy
Answer

C.

Video Solution

Done Under 90

Question 18

Phobos is one of the moons that orbits Mars. Newton’s universal law of gravitation can be applied to calculate the force between Phobos and Mars. Which one of the following conditions enables this calculation?

  1. Phobos and Mars can be considered as point masses.
  2. The distance between Phobos and Mars is large enough.
  3. Phobos and Mars both have a large volume.
  4. Phobos has a circular orbit around Mars.
Answer

A.

Video Solution

Done Under 90

Question 19

Which of the following properties is affected when a nucleus decays through gamma-decay?

  1. The proton number of the nucleus
  2. The charge of the nucleus
  3. The neutron number of the nucleus
  4. The energy state of the nucleus
Answer

D.

Video Solution

Done Under 90

Question 20

On the graph that shows how average binding energy per nucleon varies with nucleon number, the most stable elements can be found:

  1. around the minimum point of the graph.
  2. around the maximum point of the graph.
  3. near the horizontal axis intercept.
  4. near the vertical axis intercept.
Answer

B.

Video Solution

Done Under 90

Question 21

Which of the following statements is true about the Higgs boson?

  1. It has no mass, so it was difficult to observe it in experiments.
  2. It is a gauge boson.
  3. It was first predicted and later it was observed.
  4. It is positively charged.
Answer

C.

Video Solution

Done Under 90

Question 22

The SI unit combination of energy density is:

  1. J m^{3}
  2. J m^{-3}
  3. J kg
  4. J kg^{-1}
Answer

B.

Video Solution

Done Under 90

Question 23

What part of the nuclear power plant conveys energy from the reactors to the turbines?

  1. Control rods
  2. Moderator
  3. Heat exchanger
  4. Reactor vessel
Answer

C.

Video Solution

Done Under 90

Question 24

An object on a spring oscillates with simple harmonic motion (SHM) on Earth. Which of the following statements is true about the period of this system?

  1. It is influenced by the length of the spring.
  2. It is influenced by the spring constant.
  3. It is independent of the mass of the object.
  4. It will increase when the system is taken to the Moon.
Answer

B.

Video Solution

Done Under 90

Question 25

The Doppler effect:

  1. Occurs for light waves only.
  2. Occurs for sound waves only.
  3. Occurs both for light waves and sound waves.
  4. Occurs neither for light nor for sound waves.
Answer

C.

Video Solution

Done Under 90

Question 26

At infinity:

  1. only electrical potential is defined to be zero.
  2. only gravitational potential is defined to be zero.
  3. neither electrical nor gravitational potential is defined to be zero.
  4. both electrical and gravitational potential are defined to be zero.
Answer

D.

Video Solution

Done Under 90

Question 27

Which of the following quantities is needed in order to calculate the orbital speed of a satellite about a planet?

  1. The mass of the satellite
  2. The mass of the planet
  3. The distance of the satellite from the surface of the planet
  4. The radius of the planet
Answer

B.

Video Solution

Done Under 90

Question 28

The direction of the current induced in a conductor is such as to oppose the change that created the current. This statement is:

 

  1. only true for alternating currents.
  2. only true for direct currents.
  3. equivalent to Lenz’s law.
  4. equivalent to Faraday’s law of induction.
Answer

C.

Video Solution

Done Under 90

Question 29

What is definitely true about an ideal transformer?

  1. The power input is larger than the power output.
  2. There are fewer turns on the primary coil than on the secondary coil.
  3. The current in the primary coil is the same as in the secondary coil.
  4. All of the magnetic flux produced by the primary coil is entirely linked to the secondary coil. 
Answer

D.

Video Solution

Done Under 90

Question 30

An electron and an antineutrino are emitted in:

  1. \alpha decay
  2. \beta ^{-} decay
  3. \beta ^{+} decay
  4. \gamma decay
Answer

B.

Video Solution

Done Under 90

Question 31

The initial number of nuclides in a pure sample of radioactive isotope is N_{0}. Which graph correctly shows how N, the number of undecayed nuclides in the sample varies with time?

Answer

B.

Video Solution

Done Under 90

Paper 2

Question 1

A helicopter is lifting a skydiver vertically upwards at constant speed. 

a. State the net force that acts on the skydiver.

   [1 mark]

When the helicopter reaches a certain distance above the ground, the skydiver drops from the helicopter vertically downwards.

b. Draw a free body diagram

i. for the skydiver the moment after she has dropped from the helicopter.

  [1 mark]

ii. for the helicopter the moment after the skydiver has dropped from it.

  [2 marks]

While the helicopter pilot is waiting for the skydiver to reach the ground, the helicopter is hovering motionless above the ground.

c. Outline how the lift force on the helicopter is achieved. In your answer, refer to Newton’s third law of motion.

  [2 marks]

Answer 1a

Zero

Video Solution 1a

Answer 1b(i)

 

 

Answer 1b(ii)

 

 

Video Solution 1b(i &ii)

Answer 1c

The rotating helicopter blades exert a downward force on the air.

The air exerts an upward force on the blades that has the same magnitude as the downward force exerted by the blades.

Video Solution 1c

Question 2

An expandable balloon is filled with a fixed mass of argon-40 gas. The pressure of the gas is maintained at 1.3 kPa. The graph shows how the volume of the gas varies with temperature.

a. State two assumptions of the kinetic model of an ideal gas.

  [2 marks]

b. Explain why argon-40 behaves as an ideal gas for temperatures between 20 \: ^{\circ}C and 70 \: ^{\circ}C.

  [2 marks]

c. Find the mass of the argon-40 gas in the balloon.

  [2 marks]

Answer 2a

Any two of the following:

Gas molecules are considered tiny, point-like particles that have the same mass.

The volume of each molecule is negligible compared to the total volume of the gas.

Intermolecular forces between the particles are negligible.

The gas molecules only have kinetic energy.

All collisions that take place are elastic.

The duration of collisions is negligible compared to the time between collisions.

At any moment, the number of molecules moving in one direction is the same as the number of molecules moving in any other direction.

The effects of gravity are ignored.

Video Solution 2a

Answer 2b

If argon behaves as an ideal gas, then the ideal gas equation should work for this gas on the given temperature range. This means that at constant pressure \frac{V}{T} should be constant.

Let’s pick two points from the graph to show this:

\frac{15}{300} = 0.05

\frac{25}{500} = 0.05

This means that argon behaves as an ideal gas on the given temperature range.

Video Solution 2b

Answer 2c

n = \frac{(1.3 \times 10^{3})(15)}{(8.31)(300)} \approx 7.82 moles

The molar mass of argon-40 is 40 grams, so the mass of the gas in the container is (7.82)(40) \approx 313 \approx 310 grams

Video Solution 2c

Question 3

A pulse is travelling on a string that has one end fixed to a wall.

When the pulse reaches the wall, it is reflected. 

a. Sketch the pulse after it has been reflected at the wall.

  [1 mark]

The end of the string is vibrated vertically so that a transverse wave travels through the string. The time period of the vibrations is 1.62 s. The length of the string is 1.95 m.

b. Distinguish between a transverse and a longitudinal travelling wave.

   [2 marks]

c. Calculate the speed of the wave. Give your answer to an appropriate number of significant figures.

   [3 marks]

Answer 3a

 

 

Video Solution 3a

Answer 3b

In a transverse wave the displacement of the medium is perpendicular to the direction of wave propagation/energy transfer.

In a longitudinal wave the displacement of the medium is parallel to the direction of wave propagation/energy transfer.

Video Solution 3b

Answer 3c

Wavelength of the wave: \lambda = \frac{1.95}{2.5} = 0.780 m

v = f \lambda = \frac{\lambda}{T} = \frac{0.780}{1.62} \approx 0.481 m s^{-1}

Answer must be given to 3 significant figures in order to earn final mark.

Video Solution 3c

Question 4

A variable resistor is connected to a cell of internal resistance r. An ideal voltmeter is also connected to the circuit as shown.

The graph shows how the voltmeter reading varies with the current in the cell as the resistance of the variable resistor is adjusted. 

a. State what is meant by the emf of a cell.

  [2marks]

b. State the emf of the cell.

   [1 mark]

c. Find r.

  [2 marks]

Answer 4a

The work done per unit charge by the cell to move charge all the way around the circuit.

Video Solution 4a

Answer 4b

The vertical axis intercept of the graph, so 16 V

Video Solution 4b

Answer 4c

 

The internal resistance of the cell is given by the magnitude of the gradient of the graph.

Picking two points from the graph we get:

\frac{5 - 16}{2.25 - 0} \approx -4.9

So the internal resistance is 4.9 \: \Omega

Video Solution 4c

Question 5

An object of mass 2.3 kg  is moving in a vertical circle of radius 5.1 m at constant speed in an anticlockwise direction. 

a. When the object is at the position shown on the diagram, state the direction of:

i. the object’s velocity.

ii. the net force on the object.

   [2 marks]

The magnitude of the net force that acts on the object is 37 N.

b. Calculate the angular velocity of the object. Include an appropriate SI unit with your answer.

  [2 marks]

c. Determine the kinetic energy of the object.

   [2 marks]

d. Explain why the kinetic energy of the object is constant.

   [2 marks]

Answer 5a(i)

Downwards

Answer 5a(ii)

To the right/towards the centre of the circle.

Video Solution 5a (i &ii)

Answer 5b

\omega = \sqrt{\frac{37}{\left ( 2.3 \right )\left ( 5.1 \right )}} \approx 1.8 rad s^{-1}

Video Solution 5b

Answer 5c

v = (1.78)(5.1) \approx 9.1 m s^{-1}

E_{k} = \frac{1}{2}\left ( 2.3 \right )\left ( 9.1 \right )^{2} \approx 95 J

Video Solution 5c

Answer 5d

The acceleration and the velocity of the object are perpendicular to each other, so the speed of the object is unchanged. 

We can assume that the mass of the object is also unchanged and since kinetic energy depends on mass and speed, kinetic energy is constant.

Video Solution 5d

Question 6

The graph shows how binding energy per nucleon E_{B} varies with nucleon number A.

a. Use the letter S to label the region of most stable elements on the graph.

   [1 mark]

The following equation shows the fission of plutonium-239.

_{\, \, \, 94}^{239}\textrm{Pu} + X\rightarrow _{\, \, \, 54}^{134}\textrm{Xe} + _{\, \, \, 40}^{103}\textrm{Zr} + 3X

b. Write down the name of particle X.

   [1 mark]

c. Use the graph to calculate the energy released in this fission reaction. Give your answer in pJ.

   [3 marks]

Answer 6a

Region around the peak of the graph is labeled S.

 

Video Solution 6a

Answer 6b

Neutron

 

Video Solution 6b

Answer 6c

Reading values from the graph (accept a range of values here)

(134 \times 8.35 + 103 \times 8.55) - 239 \times 7.55 \approx 195 MeV

Converting into joules: 

(195 \times 10^{6})(1.6 \times 10^{-19}) \approx 3.12 \times 10^{-11} J = 31.2 pJ

Video Solution 6c

Question 7

The diameter of the area swept out by the blades of a wind turbine is 126 m. The average wind speed at the location of the turbine is 6.7 m s^{-1} and air density is 1.22 kg m^{-3}. 

a. Calculate, in MW, the maximum power output of the wind turbine. Give your answer to an appropriate number of significant figures.

   [3 marks]

b. State one reason why the result is question part (a) is a maximum.

   [1 mark]

c. Outline, without a calculation, what happens to the maximum power output of the turbine when the length of its blades are halved and wind speed is doubled.

  [2 marks]

Answer 7a

P = \frac{1}{2}(\pi \times 63^{2})(1.22)(6.7^{3}) \approx 2.288 \times 10^{6} W \approx 2.3 MW

Final answer must be given to 2 significant figures.

Video Solution 7a

Answer 7b

Some energy is lost as heat due to friction between the moving parts of the turbine.

Not all the air that enters the turbine hits the blades.

The speed of the wind that leaves the blades is not zero.

Video Solution 7b

Answer 7c

Considering the formula P = \frac{1}{2}A \rho v^{3}:

Halving the diameter means that the area swept out by the blades decreases fourfold, so power output decreases fourfold.

Doubling the wind speed means that power output increases eightfold.

The combined effect of these changes means that the maximum power output of the turbine is doubled.

Video Solution 7c

Question 8

Monochromatic light is incident on two slits and forms an interference pattern on a screen. The diagram shows the intensity of the pattern on the screen.

The separation of the slits is 0.83 mm and the distance between the slits and the screen is 5.7 m.

a. Explain why intensity is zero at P.

   [2 marks]

The distance between the central maximum and P is 13.3 mm.

b. Calculate the wavelength of the incident light.

   [2 marks]

c. State two changes to the intensity pattern when two slits are replaced by ten slits.

   [2 marks]

Answer 8a

The diagram shows the combined effects of the double-slit and single-slit patterns.

The single-slit pattern has a minimum at P.

Destructive interference at P results in zero intensity.

Video Solution 8a

Answer 8b

Distance between bright fringes on the screen:

\frac{13.3 \times 10^{-3}}{4} = 3.325 \times 10^{-3} m

\lambda = \frac{(3.325 \times 10^{-3})(0.83 \times 10^{-3})}{5.7} \approx 4.8 \times 10^{-7} m or 480 nm

Video Solution 8b

Answer 8c

The fringes on the screen become more narrow.

The intensity of the bright fringes increases.

Video Solution 8c

Question 9

A particle of mass 7.2 \times 10^{-18} kg and charge Q is moved from point A to point B.

a. Outline what is meant by gravitational potential at a point.

   [2 marks]

The following data are provided:

Gravitational potential at A: 38M J kg^{-1}

Gravitational potential at B: -45 MJ kg^{-1}

Electric potential at A: 21 mV

Electric potential at B: 8.7 mV

Work done when moving the particle: 480 pJ

b. Outline why the work done by the gravitational field on the particle is positive.

   [1 mark]

c. Determine, in nC, the charge of the particle.

  [3 marks]

Answer 9a

The work done per unit mass when moving a test mass from infinity to the point.

Video Solution 9a

Answer 9b

The particle moves from a higher to a lower gravitational potential, so the work done by the field is positive.

Video Solution 9b

Answer 9c

Since work is done (energy is supplied to the system) to move the particle from A to B, the total work done by the two fields is negative.

W_{total} = -(m \Delta V_{g} + q \Delta V_{e})

480 \times 10^{-12} = -((7.2 \times 10^{-18})(-83 \times 10^{6}) + (Q)(-12.3 \times 10^{-3}))

Q \approx -9.56 \times 10^{-9} C \approx -9.6 nC

Video Solution 9c