Physics

Assessment Objectives

1. Demonstrate knowledge and understanding of:• facts, concepts and terminology• methodologies and techniques• communicating scientific information.

2. Apply:• facts, concepts and terminology• methodologies and techniques• methods of communicating scientific information.

3. Formulate, analyse and evaluate:• hypotheses, research questions and predictions• methodologies and techniques• primary and secondary data• scientific explanations.

4. Demonstrate the appropriate research, experimental, and personal skills necessary to carry out insightful and ethical investigations.

Assessment Outline

SL

Assessment component WeightingPaper 1 20%Paper 2 40%Paper 3 20%Internal Assessment 20%

HL

Assessment component WeightingPaper 1 20%Paper 2 36%Paper 3 24%Internal Assessment 20%

Assessment details

SL

Paper 1Duration: ¾ hour • 30 multiple-choice questions on core, about 15 of which are common

with HL.• The questions on paper 1 test assessment objectives 1, 2 and 3.• The use of calculators is not permitted.• No marks are deducted for incorrect answers.• A physics data booklet is provided.

Example exam question.Physics Standard Level Paper 1.

The graph shows the variation with volume V of the pressure p of a fixed mass of an ideal gas as the temperature of the gas is raised.

What is the work done by the gas during the process?A. 0.5 kJB. 1.0 kJ

C. 1.5 kJD. 2.0 kJ

What is thermal conduction mainly due to in a gas?A. The motion of free electronsB. Fast molecules transferring energy to slower moleculesC. Slow molecules transferring energy to faster moleculesD. Lattice vibrations causing collisions with neighbouring molecules

Paper 2Duration: 1¼ hours • Short-answer and extended-response questions on core material.• The questions on paper 2 test assessment objectives 1, 2 and 3.• The use of calculators is permitted. (See calculator section on the OCC.)• A physics data booklet is to be provided by the school.

Example exam question.Physics Standard Level Paper 2.

In the drop tower shown, containers with experiments inside of them are fired upwards inside a vertical tower.

The container moves under the influence of gravity and eventually falls back to the bottom of the tower. Most of the air is removed from the tower so that air resistance is negligible. While in flight, the container and its contents are in free-fall.

(a) The container is fired vertically upwards with initial speed 48 m s–1. Determine the time that the container is in flight. (2)

(b) At the end of the flight, the container of total mass 480 kg falls into a

tank of expanded Styrofoam (polystyrene) spheres to slow it. The container stops after moving a distance of 8.0 m in the Styrofoam. Calculate the average force that acts on the container due to the spheres. (3)

(c) Outline why the experiments inside the container could be considered to be in “weightless” conditions. (2)

(d) The tower is 120 m high with an internal diameter of 3.5 m. When most of the air has been removed, the pressure in the tower is 0.96 Pa.(i) Determine the number of molecules of air in the tower when

the temperature of the air is 300 K. (3) (ii) Outline whether the behaviour of the remaining air in the tower

approximates to that of an ideal gas. (2) (e) The container can also be released from rest at the top of the tower.

The graph shows how the container velocity varies with time from release with the tower in a partial vacuum.

(i) State the quantity that is represented by the shaded area ABC. (1)

(ii) Air is introduced into the tower. The container is released from the top of the tower when the air in the tower is at atmospheric pressure. Using the axes in (e), sketch a graph to show how the container velocity varies with time from release when the air is at atmospheric pressure.

Paper 3Duration: 1 hour• This paper will have questions on core and SL option material.• Section A: one data-based question and several short-answer questions

on experimental work.• Section B: short-answer and extended-response questions from one

option.• The questions on paper 3 test assessment objectives 1, 2 and 3.• The use of calculators is permitted. (See calculator section on the OCC.)• A physics data booklet is to be provided by the school.

Example exam question.Physics Standard Level Paper 3

In an experiment to measure the specific heat capacity of a metal, a piece of metal is placed inside a container of boiling water at 110000 °C. The metal is then transferred into a calorimeter containing water at a temperature of1 1000 °C. The final equilibrium temperature of the water was measured. One source of error in this experiment is that a small mass of boiling water will be transferred to the calorimeter along with the metal.

(a) Suggest the effect of the error on the measured value of the specific heat capacity of the metal.(2)

(b) State one other source of error for this experiment.(1)

Option B — Engineering physics

A bucket of mass m is held above a water well by a rope of negligible mass, as shown. The rope is wound around a cylinder of mass M and radius R. The moment of inertia of the cylinder about its axis

is

(a) Show that the acceleration a of the bucket is given by the following equation. (4)

(b) The following data are available.Bucket mass m = 24 kgCylinder mass M = 36 kgRadius R = 0.20 m(i) Calculate the speed of the bucket when it has fallen a distance of

16 m from rest. (2)(ii) Calculate the rate of change of the angular momentum of the

cylinder.(3)

(c) The bucket in (b) is filled with water so its total mass is now 45 kg. The bucket israised at a constant speed of 2.0 m s–1 using an electric motor attached to the cylinder.Calculate the power output of the motor. (1)

HL Assessment overview

Paper 1Duration: 1 hour• 40 multiple-choice questions on core and AHL, about 15 of which are

common with SL.• The questions on paper 1 test assessment objectives 1, 2 and 3.• The use of calculators is not permitted.• No marks are deducted for incorrect answers.• A physics data booklet is provided.

Example exam question.Physics Higher Level Paper 1.

1 A mass hangs freely from the end of a spring. A student raises the mass vertically until the tension in the spring becomes zero. The gain in gravitational potential energy of the mass is equal to the work done

A. by the student against the force of gravity acting on the mass.B. on the mass by the student plus the elastic potential energy lost by

the spring.

C. on the mass by the student minus the elastic potential energy lost by the spring.

D. on the mass by the student minus the work done on the mass by the tension in the spring.

2 Two separate sealed containers hold air at the same temperature. They are connected by a thin tube containing a valve. Initially one container holds 0.2 m3 of air at a pressure of 50 kPa and the other container holds 0.3 m3 of air at a pressure of 20 kPa.

The valve is slowly opened and the temperature stays constant. What is the final pressure in the containers?A. 32 kPaB. 35 kPaC. 38 kPaD. 70 kPa

Paper 2Duration: 2¼ hours • Short-answer and extended-response questions on the core and AHL

material.• The questions on paper 2 test assessment objectives 1, 2 and 3.• The use of calculators is permitted. (See calculator section on the OCC.)• A physics data booklet is to be provided by the school.

Example exam question.Physics Higher Level Paper 2.

A circuit is designed to supply regular pulses of charge to a 3.3 kΩ resistor using an electronic switch S.

Initially the capacitor is uncharged. The battery has a negligible internal resistance.

The capacitance of the capacitor is 4.7 μF.

(a) At time t = 0 the switch is moved to position 1. Using the axes, draw a graph to show how the potential difference V across the capacitor varies with time t as it charges. A time scale is not required. (2)

(b) A single pulse of charge is produced by moving the switch S to position 2 for 6.3 ms.(i) Show that the potential difference across the capacitor falls

by about 2 V during the duration of the pulse. (3)(ii) Calculate the charge that flows through the circuit during the

pulse.(iii) The battery has a charge capacity of 0.55 Ah and the circuit

produces one pulse each second. Calculate the time, in years, for which the battery can operate the circuit.

(iv) Two batteries in series, each of emf 6.0 V and having negligible internal resistance, replace the single battery. All other components in the circuit remain the same. Compare the energy transferred from the two batteries with the energy transferred from the single battery during one charge–discharge cycle.

Paper 3Duration: 1¼ hours • This paper will have questions on core, AHL and option material.• Section A: one data-based question and several short-answer questions

on experimental work.• Section B: short-answer and extended-response questions from one

option.• The questions on paper 3 test assessment objectives 1, 2 and 3.• The use of calculators is permitted. (See calculator section on the OCC.)• A physics data booklet is provided.

Example exam question.Physics Higher Level Paper 3.

A rocket of proper length 900 m is moving at speed 0.80c relative to the Earth. E is a reference frame in which the Earth is at rest. R is a reference frame in which the rocket is at rest. The diagram is from the point of view of E.

(a) A light signal is emitted from the back of the rocket and is received at the front ofthe rocket.

Determine the

(i) time interval between the emission and reception of the light signal according toan observer in R. (1)

(ii) time interval between the emission and reception of the light signal according toan observer in E. (3)

(iii) distance separating the emission and reception of the light signal according toan observer in E. (1)

(b) One photon is emitted from the back B of the rocket and another photon is emitted from the front F of the rocket, as shown.

The emissions are simultaneous according to observers in R. The photons are receivedby an observer at rest in the middle of the rocket.The spacetime diagram represents the reference frame of the Earth E and the rocketframe R. The coordinates in frame E are x and ct and in frame R they are x′and ct′.The position of the back B and of the front F of the rocket at t= 0 are labelled.The origin of the axes corresponds to the middle of the rocket.

(i) On the spacetime diagram, draw lines to show the worldlines of the photons fromwhen they were emitted to when they were received. (3)

(ii) Using the spacetime diagram, determine which photon was emitted first accordingto observers in E. (2)

(iii) Determine the time separating the emissions of the two photons according toobservers in E. (2)

(c) A missile is launched from the rocket. The velocity of the missile is – 0.62c relative to the rocket. Calculate the velocity of the rocket relative to the Earth. (3)

Command terms with definitions

Command terms for Assessment Objective 1: Demonstrate Knowledge and Understanding.

Command Term DefinitionDefine Give the precise meaning of a word, phrase, concept

or physical quantity.Draw Represent by means of a labelled, accurate diagram

or graph, using a pencil. A ruler (straight edge) should be used for straight lines. Diagrams should be drawn to scale. Graphs should have points correctly plotted (if appropriate) and joined in a straight line or smooth curve.

Label Add labels to a diagram.

List Give a sequence of brief answers with no explanation.Measure Obtain a value for a quantity.State Give a specific name, value or other brief answer

without explanation or calculation.Write down Obtain the answer(s), usually by extracting

information. Little or no calculation is required. Working does not need to be shown.

Command terms for Assessment Objective 2: Apply

Command Term DefinitionAnnotate Add brief notes to a diagram or graph.Apply Use an idea, equation, principle, theory or law in

relation to a given problem or issue.Calculate Obtain a numerical answer showing the relevant

stages in the working (unless instructed not to do so).Describe Give a detailed account.Distinguish Make clear the differences between two or more

concepts or items.Estimate Obtain an approximate value.

Formulate Express precisely and systematically the relevant concept(s) or argument(s).

Identify Provide an answer from a number of possibilities.Outline Give a brief account or summary.Plot Mark the position of points on a diagram.

Command terms for Assessment Objective 3: Formulate, analyse and evaluate:

Command Term DefinitionAnalyse Break down in order to bring out the essential

elements or structure.Comment Give a judgment based on a given statement or result

of a calculation.Compare Give an account of the similarities between two (or

more) items or situations, referring to both (all) of them throughout.

Compare and contrast

Give an account of the similarities between two (or more) items or situations, referring to both (all) of them throughout.

Construct Display information in a diagrammatic or logical form.Deduce Reach a conclusion from the information given.Demonstrate Make clear by reasoning or evidence, illustrating with

examples or practical application.Derive Manipulate a mathematical relationship to give a new

equation or relationship.Design Produce a plan, simulation or model.Determine Obtain the only possible answer.Discuss Offer a considered and balanced review that includes

a range of arguments, factors or hypotheses. Opinions or conclusions should be presented clearly and supported by appropriate evidence.

Evaluate Make an appraisal by weighing up the strengths and limitations.

Explain Give a detailed account including reasons or causes.Hence Use the preceding work to obtain the required result.Hence or otherwise

It is suggested that the preceding work is used, but other methods could also receive credit.

Justify Give valid reasons or evidence to support an answer or conclusion.

Predict Give an expected result.Show Give the steps in a calculation or derivation.Show that Obtain the required result (possibly using information

given) without the formality of proof. “Show that” questions do not generally require the use of a calculator.

Sketch Represent by means of a diagram or graph (labelled as appropriate). The sketch should give a general idea of the required shape or relationship, and should include relevant features.

Solve Obtain the answer(s) using algebraic and/or numerical and/or graphical methods.

Suggest Propose a solution, hypothesis or other possible answer.