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Free Physics diagnostic test.
Eight focused questions. Clear explanations. A practical next step for every mistake. Choose your course and check a sample of the skills you have already studied.
By Dr Desouky Physics Academy · Independent study guidance, not an exam-board assessment or endorsement.
A topic check, not a predicted grade
These original questions sample a few concepts from each course. They do not assess the whole syllabus, extended written answers or your performance under examination conditions. Your result is a count of correct answers on this exercise, with no conversion to an A*, a 9 or an official grade.
Allow about 10–15 minutes, use a calculator and write your working on paper. If a topic has not been taught yet, leave it unanswered and read its explanation afterwards. Unsure which course to choose? Use the Physics exam-board finder.
Choose your diagnostic
A sample of IGCSE foundations, including motion, circuits, practical thinking and space Physics. It is not a complete Core or Extended paper. Changing your course resets this attempt.
Answers and results stay in this page’s memory and are cleared when you reload. No email or name is required. Answer choices and scores are not sent to analytics or included in the enquiry link.
All worked answers
The complete question sets and solutions are free to read, including without JavaScript. Open a course, try each question on paper, then open its answer. Each explanation links to the next useful revision resource.
Cambridge IGCSE Physics — 8 worked answers
A sample of IGCSE foundations, including motion, circuits, practical thinking and space Physics. It is not a complete Core or Extended paper.
1. A track is 240 cm long. What length should you substitute into an equation that requires metres?
Show worked answer
2.40 m
There are 100 cm in 1 m, so 240 ÷ 100 = 2.40 m. Write the conversion before substituting: an otherwise correct formula can still produce a wrong answer if the units are inconsistent.
Unit conversion practice →2. Velocity increases uniformly from 2 m/s to 10 m/s in 4 s. What is the acceleration?
Show worked answer
2 m/s²
Acceleration = change in velocity ÷ time = (10 − 2) ÷ 4 = 2 m/s². On a velocity–time graph this is the gradient. Dividing the final velocity by time would incorrectly assume the initial velocity was zero.
Motion and acceleration →3. A car travels in a straight line at constant velocity on a level road. What is the resultant force on it?
Show worked answer
Zero
Constant velocity means zero acceleration, so the resultant force is zero. Forces can still act: the driving force balances the resistive forces, and the vertical forces balance. Zero resultant force does not require the car to be stationary.
Forces and motion →4. A motor transfers 600 J of energy in 20 s. What is its average power?
Show worked answer
30 W
Power is the rate of energy transfer: P = E/t = 600/20 = 30 W. One watt is one joule per second. Multiplying energy by time does not give power.
Energy, work and power →5. A 3 Ω resistor and a 6 Ω resistor are in series across an ideal 18 V supply. What current passes through the 6 Ω resistor?
Show worked answer
2 A
The total series resistance is 3 + 6 = 9 Ω. The circuit current is I = V/R = 18/9 = 2 A, and the same current passes through each series component. The 6 Ω resistor does not have the full 18 V across it.
Electric circuits →6. A wave has frequency 50 Hz and wavelength 0.40 m. What is its speed?
Show worked answer
20 m/s
Use v = fλ: 50 × 0.40 = 20 m/s. Frequency means 50 waves pass a point each second; each wavelength is 0.40 m long. This gives 20 metres travelled by the wave in one second.
Waves and the wave equation →7. You investigate how the length of a wire affects its resistance. Which plan best makes the comparison fair?
Show worked answer
Keep material, cross-sectional area and temperature the same
Changing one independent variable lets you connect the result to that change. Material, cross-sectional area and temperature also affect resistance, so keep them controlled. Heating the wire introduces a second influence on the measured resistance.
Resistance and circuit measurements →8. A distant galaxy’s spectral lines are observed at longer wavelengths than their laboratory values. What is this called?
Show worked answer
Redshift
A shift towards longer wavelengths is redshift. In the context of distant galaxies, cosmological redshift is evidence associated with the expansion of the Universe. Identify the wavelength change first; brightness alone would not establish a redshift.
Cambridge IGCSE Space Physics →
Edexcel International GCSE Physics — 8 worked answers
Selected shared foundations for linear and modular International GCSE Physics. Questions are not organised as a specific 4PH1 paper or 4XPH1 unit.
1. An object has mass 180 g and volume 60 cm³. What is its density?
Show worked answer
3.0 g/cm³
Density = mass/volume = 180/60 = 3.0 g/cm³. These units are consistent with the supplied mass and volume. If an answer in kg/m³ is required, multiply this value by 1000 to obtain 3000 kg/m³.
Mass, weight and density →2. An object travels at 6 m/s for 5 s. What does the rectangular area under its speed–time graph represent?
Show worked answer
30 m travelled
Area under a speed–time graph gives distance: 6 m/s × 5 s = 30 m. Its gradient is zero because the speed is constant. A graph’s area and gradient answer different questions.
Graph gradients and areas →3. A force of 12 N acts perpendicular to a lever, 0.25 m from its pivot. What is the moment?
Show worked answer
3.0 N m
Moment = force × perpendicular distance from the pivot = 12 × 0.25 = 3.0 N m. The distance must be perpendicular to the force’s line of action. Although N m is dimensionally equivalent to a joule, moments are conventionally stated in N m.
Moments and turning effects →4. A device receives 500 J and transfers 150 J usefully. What is its efficiency?
Show worked answer
30%
Efficiency = useful output energy/input energy × 100% = 150/500 × 100% = 30%. The remaining 350 J is transferred in less useful ways. An energy efficiency above 100% would conflict with conservation of energy.
Energy efficiency →5. Two 6 Ω resistors are connected in parallel across an ideal 12 V supply. What is the total supply current?
Show worked answer
4 A
Each parallel branch has 12 V across it, so each branch current is 12/6 = 2 A. The supply current is the sum, 2 + 2 = 4 A. Equivalently, the combined resistance is 3 Ω, giving 12/3 = 4 A.
Series and parallel circuits →6. Light passes from air into glass. Which quantity remains unchanged at the boundary?
Show worked answer
Frequency
The source fixes the frequency, so it stays the same across the boundary. Light travels more slowly in glass. Since v = fλ, the wavelength decreases when the speed decreases while frequency remains constant.
Light and refraction →7. A radioactive sample’s activity falls from 800 Bq to 100 Bq. Background has already been subtracted. How many half-lives have elapsed?
Show worked answer
3
Halve in stages: 800 → 400 → 200 → 100 Bq. That is three half-lives. A half-life is a repeated fractional reduction, not a fixed subtraction of the same number of becquerels.
Radioactivity and half-life →8. A balance reads +2 g when empty. You take five mass readings and calculate their mean. Does averaging remove this zero error?
Show worked answer
No; check and correct the zero error
A zero error biases each reading in the same direction. Averaging can reduce the effect of random variation, but it does not remove a fixed +2 g offset. Zero the balance correctly or apply an appropriate correction after checking the instrument.
Measurements and errors →
Edexcel International AS Physics — 8 worked answers
An IAS foundations check for students studying mechanics, materials, waves, electricity and practical skills. Take it after studying these topics, not as an admissions test.
1. A wire has cross-sectional area 0.50 mm². What is this in m²?
Show worked answer
5.0 × 10⁻⁷ m²
1 mm = 10⁻³ m, so 1 mm² = (10⁻³)² m² = 10⁻⁶ m². Therefore 0.50 mm² = 0.50 × 10⁻⁶ = 5.0 × 10⁻⁷ m². Squared dimensions require the conversion factor to be squared.
Squared and cubed unit conversions →2. An object starts at 3.0 m/s and accelerates uniformly at 2.0 m/s² for 4.0 s. Find its displacement.
Show worked answer
28 m
Use s = ut + ½at² = 3.0 × 4.0 + ½ × 2.0 × 4.0² = 12 + 16 = 28 m. The equation assumes constant acceleration. The final velocity is 11 m/s; using 11 × 4 would incorrectly treat it as constant throughout.
Kinematics and constant acceleration →3. A 0.20 kg trolley moving at 3.0 m/s sticks to a stationary 0.40 kg trolley. External impulse is negligible. What is their common velocity?
Show worked answer
1.0 m/s in the original direction
Initial momentum = 0.20 × 3.0 = 0.60 kg m/s. Final mass = 0.60 kg, so v = 0.60/0.60 = 1.0 m/s. Momentum is conserved under the stated assumption, but kinetic energy is not conserved in this sticking collision.
Dynamics and momentum →4. A wire is stretched within its linear elastic region. Stress is 2.0 × 10⁸ Pa and strain is 1.0 × 10⁻³. What is the Young modulus?
Show worked answer
2.0 × 10¹¹ Pa
Young modulus E = stress/strain = (2.0 × 10⁸)/(1.0 × 10⁻³) = 2.0 × 10¹¹ Pa. Strain is a ratio of lengths and has no unit. The linear elastic condition makes this ratio the appropriate modulus.
Deformation of solids →5. Two points on a progressive sinusoidal wave are separated by one quarter of a wavelength. What is their phase difference?
Show worked answer
π/2 rad
One full wavelength corresponds to 2π radians. For a separation λ/4, phase difference = 2π × (λ/4)/λ = π/2 radians, or 90°. This compares the oscillations at the same instant.
Waves and superposition →6. A cell has emf 6.0 V and internal resistance 1.0 Ω. It supplies a current of 0.50 A. What is its terminal potential difference?
Show worked answer
5.5 V
For a cell supplying current, terminal p.d. V = ε − Ir = 6.0 − 0.50 × 1.0 = 5.5 V. The 0.50 V difference is across the internal resistance. Emf and terminal p.d. are equal only when the current is zero in this model.
Electricity and internal resistance →7. A length is recorded as (25.0 ± 0.5) cm. What is the percentage uncertainty?
Show worked answer
2.0%
Percentage uncertainty = absolute uncertainty/measured value × 100% = 0.5/25.0 × 100% = 2.0%. Use matching units in the ratio. The percentage uncertainty is not the same thing as percentage error relative to an accepted value.
Percentage uncertainty with worked examples →8. A spring follows F = kx. You plot force F vertically against extension x horizontally, using N and m. What does the gradient represent?
Show worked answer
k, measured in N/m
Compare F = kx with y = mx: F is vertical, x is horizontal and k is the gradient. Its units are N/m. Reversing the axes would instead give 1/k. Use a large triangle on the fitted straight line when measuring the gradient.
Physics graph skills →
Edexcel International A-Level / A2 Physics — 8 worked answers
Selected A2 concepts and practical reasoning, building on IAS knowledge. It is not a full YPH11 qualification test, and students starting IAS should choose the IAS path first.
1. An object travels at 6.0 m/s around a circle of radius 2.0 m. What is its centripetal acceleration?
Show worked answer
18 m/s²
Centripetal acceleration a = v²/r = 6.0²/2.0 = 18 m/s², directed towards the centre. Constant speed does not mean zero acceleration here: the velocity direction changes continuously.
Circular motion →2. An ideal uniform field between parallel plates has potential difference 600 V across a 0.020 m gap. What is the field strength magnitude?
Show worked answer
3.0 × 10⁴ V/m
For the ideal uniform field, E = V/d = 600/0.020 = 3.0 × 10⁴ V/m. This formula uses the plate separation along the field direction and neglects edge effects. V/m is equivalent to N/C.
Electric fields →3. A 100 μF capacitor is charged to 12 V. How much energy does it store?
Show worked answer
7.2 × 10⁻³ J
Convert 100 μF to 1.0 × 10⁻⁴ F. Energy = ½CV² = ½ × 1.0 × 10⁻⁴ × 12² = 7.2 × 10⁻³ J. QV would be twice the stored energy because the capacitor p.d. rises as it charges.
Capacitance and stored energy →4. In simple harmonic motion, where is the magnitude of acceleration greatest?
Show worked answer
At either maximum displacement
For SHM, a = −ω²x, so acceleration magnitude is proportional to displacement magnitude. It is greatest at either extreme and zero at equilibrium. At the extremes the velocity is instantaneously zero, showing that zero velocity does not imply zero acceleration.
Oscillations and SHM →5. A fixed amount of ideal gas is heated from 300 K to 450 K at constant volume. How does its pressure change?
Show worked answer
It increases by a factor of 1.5
From pV = nRT, p/T is constant when n and V are fixed. Therefore p₂/p₁ = T₂/T₁ = 450/300 = 1.5. Gas-law temperature ratios must use kelvin, not degrees Celsius.
Temperature and ideal gases →6. A charged particle moves through a uniform magnetic field with its velocity parallel to the field. What is the magnetic force on it?
Show worked answer
Zero
Magnetic force magnitude is F = |q|vB sin θ. With parallel velocity and field, θ = 0 and sin θ = 0, so the magnetic force is zero. The formula F = |q|vB applies only when the motion is perpendicular to the field.
Magnetic fields and moving charges →7. A radionuclide has decay constant λ = 0.020 s⁻¹. What is its half-life, approximately?
Show worked answer
35 s
Half-life t½ = ln 2/λ = 0.693/0.020 = 34.65 s, approximately 35 s. The quantity 1/λ = 50 s is the mean lifetime for exponential decay, not the half-life.
Nuclear Physics and decay →8. For a simple pendulum at small amplitude, T² = (4π²/g)L. You plot T² vertically against L horizontally. How do you obtain g from gradient m?
Show worked answer
g = 4π²/m
Compare the equation with y = mx: the gradient m is 4π²/g, with units s²/m. Rearranging gives g = 4π²/m. Squaring T is the transformation that makes the expected relationship linear; a T against L graph would be curved.
Linear graphs and practical skills →
Turn the feedback into a revision session
- Name the error. Was it the idea, the equation, the units or the arithmetic? Copying a correct final answer does not fix the step you missed.
- Rebuild the method. Follow the linked notes and write the explanation in your own words. Then attempt a fresh question with different numbers or a different context.
- Come back later. Add the topic to your Physics revision planner and test it again without looking at the solution.
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