Practice Paper 1A (HL IB Physics)

The image shows a block resting on an inclined plane. 

Which row in the table gives the correct interpretation of the forces acting on the block, R, F and W?

The efficiency of an electric motor is 80 %. When lifting a body, the amount of energy wasted is . What is the useful work done by the motor?

Two co-planar forces of equal magnitude F act on the rim of a wheel.

Which pair of forces act as a couple on the wheel?

Cars A and B are driving on a motorway heading in the same direction. Car A is travelling at a constant velocity of 30 m s^-1 and Car B is travelling at constant velocity of 40 m s^-1, both relative to a farmer in a field observing the cars go by. Car B overtakes Car A in the next lane.

What speed is Car B traveling at from the reference frame of Car A?

On a space-time diagram, the units of time are metres. 

Event A occurred 10 seconds after event B.

Which value is equal to 1 second on the spacetime diagram?

Baseball player Y throws a ball to baseball player X as shown. 

What is the direction of the net force on the ball at the instant shown, if air resistance is not neglected? 

A ball attached to a string rotates in a gravitational field with a constant time period in a vertical plane. The forces acting on the mass are tension, T and weight, W.

What is an expression for the magnitude of the tension in the string at the top of the circle?

The diagram shows a pulley in a crane system. An elevator m₁ is used to lift building materials.  A counterbalance m₂ is used in the system. g is the acceleration due to free fall. 

What rate does the motor provide energy to the system when the elevator is rising at a steady speed v m s⁻¹?

A wooden block of weight W rests on a rough board that produces a friction force F_f. The end of the board is then raised up to angle θ until the block slides down the plane of the board at constant velocity v.

Which row describes the forces acting on the block as it slides down the board?

A solid material of mass m is being heated. The heater applies a constant power of 150m to the solid, which has a specific heat capacity of 1.8 × 10³ J kg^–1 K^–1. The graph below shows how the temperature of the material varies with time as the solid melts and becomes a liquid.

What is the specific latent heat of fusion of the substance?

A fixed mass of an ideal gas undergoes an isovolumetric change. This leads to a decrease in the pressure of the gas.

Which row describes the change in internal energy of the gas and the direction of transfer of thermal energy?

The variation of pressure p with temperature T is shown on the graph for a fixed mass of an ideal gas at constant volume. 

What is the ratio of pressure and temperature of the ideal gas?

A simple heat engine contains 3 moles of an ideal gas. When the gas is cooled, the mean kinetic energy per particle drops by 3.11 × 10⁻²¹ J.

Additionally, 2 kJ of work is done on the gas. 

What is the thermal energy transferred from the gas to its surroundings?

In an adiabatic process, a gas in a piston does work.

The cylindrical chamber increases in length from 1.5 m to 290 cm.

Which expression, in terms of original pressure p, most closely represents the new pressure?

The diagram shows a simplified model of the energy balance of the Earth's surface.

The atmosphere and the surface of the Earth can be modelled as two black body radiators each at constant temperature. The surface of the Earth receives both solar radiation and radiation emitted from the atmosphere.

The average equilibrium temperature of the Earth's surface is T_S and the average equilibrium temperature of the atmosphere is T_A = 252 K.

What is the value of T_S?

In the two circuits shown, only the internal resistances differ.

Which row in the table below correctly describes the potential difference across and power dissipated by the 3 Ω resistor? 

Two rods have the same length and resistance. One rod is made from copper and the other from aluminium.

Copper is three times as dense as aluminium but has half the value of resistivity.

Which of the following gives the correct value of ?

A mass-spring system oscillates with simple harmonic motion. The mass m has an amplitude A and the spring has a total energy E. The mass is increased by half and the amplitude increased to 4A.

What is the total energy in the spring E_T?

A pendulum is undergoing simple harmonic motion with a time period T and angular frequency ω.

A student makes a change to the set up so that the pendulum has a new time period 3T.

What is the new angular frequency?

A longitudinal travelling wave has speed v and wavelength λ. What is the least distance between a compression and a rarefaction with respect to the direction of propagation?

Waves emitted from sources V and W are initially in phase and have equal wavelengths. Point A is not equidistant between V and W. The waves interfere destructively at point A, where the path difference is 0.30 m.  

 What is the maximum possible value of the wavelength of the waves?

Which one of the following options is always true regarding the energy transferred along a standing wave and its amplitude?

A flute is a musical instrument with a typical length, L, of 67 cm. It has a hole in the lip plate at one end which the musician blows across, and is open at the other end. 

The length of the air column is varied by opening and closing a series of keys along the side. The velocity of the air entering the lip plate is controlled by the musician.

To create a frequency f  the musician creates a wave with velocity v, holding down the keys such that the column of air is half the available length.

If she wants to increase the frequency to three times the original pitch, which changes to would achieve this?

	v	L
A.	× 9	× 2
B.	× 3	×
C.	stays the same	× 3
D.	×	×

Two lines P and Q in the emission spectrum of a gas are measured on the Earth by a stationary observer.

The observer then moves towards the gas sample, and the emission spectrum is recorded as they are moving.

What is the correct pattern for the shifted spectral lines, P' and Q'?

A train is moving away from an observer on a platform with a constant speed  where v is the speed of sound. The train emits sound of frequency f.

What is the observed speed of sound and the observed frequency as the train recedes?

	Observed speed of sound	Observed frequency
A.
B.
C.
D.

A spherical planet of uniform density has two times the mass of the Earth and three times the average radius. The magnitude of the gravitational field strength at the surface of the Earth is g. What is the gravitational field strength at the surface of the planet?

A plotting compass is placed next to a vertical wire AB. When there is no current in the wire, the compass points North due to an external magnetic field.

Which diagram shows a possible direction for the compass to point when a current passes from A to B?

A negatively charged particle is at rest in a magnetic field B. The force on the particle is:

The gravitational field strength is g and the gravitational potential is V at the surface of Earth, which has a radius of r.  

Which row in the table gives the correct value of the gravitational field strength and the gravitational potential at a height of 2r from Earth's surface? 

Two charged parallel metal plates, X and Y, are separated by a distance of 2.0 m. X is charged to a potential of –180 V and Y is charged to a potential of +180 V. 

What is the magnitude and direction of the electric field strength at a point exactly mid-way between plates X and Y? 

A square coil of conducting wire with sides of length W is moved at constant speed v left to right, through a uniform magnetic field which is directed into the page and has width W. 

From the point where the coil enters the field until the point where it leaves it, which description best fits the direction of the current induced in the coil?

A copper ring is suspended by a long, light rod pivoted at X so that it may swing as a pendulum, as shown in the diagram below:

An electromagnet is set up so that the ring can pass over it as it swings. The ring is then set into oscillation at time t = 0, with switch K open. It completes two full oscillations, at which point the switch K is closed at time t = t₀

Which graph correctly shows the variation of the displacement x with time t?   

The diagram shows four point charges at the corners of a square of sides 4a.

What is the electric potential at P, the centre of the square?

In the Geiger-Marsden-Rutherford experiment, alpha particles are fired at a thin gold foil. Two key observations of the experiment are 

1. most alpha particles pass through the foil undeflected
2. a few alpha particles are deflected by large angles

Which of the following rows correctly explains these observations?

At which scattering angle is the maximum energy transferred to an electron by a photon during Compton scattering?

One possible fission reaction of uranium-235 following the capture of a thermal neutron is:

Which statement(s) about this reaction is/are correct?

1. The binding energy of the nucleus is 206 MeV.
2. The combined rest mass of the fission products equals the rest mass of the nucleus.
3. The nucleon number is unchanged by the fission process.

Two unstable isotopes are initially present in equal numbers. Isotope Y has a half-life of 6 minutes and isotope Z has a half-life of 3 minutes.

Which expression correctly describes the ratio of the activity of Y to Z after 12 minutes?

All objects shown on a Hertzsprung-Russell diagram emit electromagnetic radiation.

Some statements about two objects R and S are:

1. R emits radiation with a higher mean frequency than S
2. The wavelength of the peak intensity of the radiation emitted by S is in the red region of the visible light spectrum
3. S and R both emit radiation with the same intensity

Which statement(s) about R and S is/are correct?

Nucleus has radius and nucleon number .

Nucleus has radius  and nucleon number .

What is the ratio of ?