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North Rhine-Westphalia Zentralabitur Physics study materials
North Rhine-Westphalia Zentralabitur Physics study resources

North Rhine-Westphalia Zentralabitur Physics practice questions

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Question 1Mechanics

A car accelerates uniformly from rest to 20 m/s in 5 s. What is its acceleration?

  1. 4 m/s^2 Correct answer.
  2. 2 m/s^2
  3. 100 m/s^2
  4. 20 m/s^2

Explanation

a = (v - v0) / t = (20 - 0) / 5 = 4 m/s^2.

Question 2Mechanics

An object in free fall (ignoring air resistance) near Earth's surface has an acceleration of approximately what value?

  1. 9.81 m/s^2 Correct answer.
  2. 0 m/s^2
  3. 3.71 m/s^2
  4. 1 m/s^2

Explanation

Near Earth's surface, gravitational acceleration g is approximately 9.81 m/s^2, a standard constant used throughout NRW Physik Mechanik problems.

Question 3Mechanics

What does Newton's second law of motion state?

  1. F = m x a (net force equals mass times acceleration) Correct answer.
  2. F = m / a
  3. An object at rest always stays in motion
  4. Force is independent of mass

Explanation

Newton's second law states that net force equals mass times acceleration (F = ma), describing how force causes acceleration proportional to mass.

Question 4Mechanics

What is the kinetic energy of a 2 kg object moving at 3 m/s?

  1. 9 J Correct answer.
  2. 6 J
  3. 18 J
  4. 3 J

Explanation

Kinetic energy Ekin = 0.5 x m x v^2 = 0.5 x 2 x 3^2 = 0.5 x 2 x 9 = 9 J.

Question 5Mechanics

What does the law of conservation of momentum state for an isolated system (no external forces)?

  1. Total momentum before an interaction equals total momentum after it Correct answer.
  2. Momentum is always destroyed in every collision
  3. Only kinetic energy is ever conserved, never momentum
  4. Momentum can be created without any external force

Explanation

In an isolated system with no external net force, the total momentum before a collision or interaction equals the total momentum afterward.

Question 6Mechanics

A 1000 kg car moving at 10 m/s has what momentum?

  1. 10,000 kg·m/s Correct answer.
  2. 100 kg·m/s
  3. 1,000 kg·m/s
  4. 10 kg·m/s

Explanation

Momentum p = m x v = 1000 kg x 10 m/s = 10,000 kg·m/s.

Question 7Mechanics

What does Newton's law of universal gravitation describe?

  1. The attractive force between two masses is proportional to their masses and inversely proportional to the square of the distance between them Correct answer.
  2. Gravity only acts on objects with electric charge
  3. Gravitational force is constant regardless of distance
  4. Gravity repels all masses from each other

Explanation

Newton's law of universal gravitation states F = G(m1 m2)/r^2, meaning gravitational attraction increases with mass and decreases with the square of the separation distance.

Question 8Mechanics

What is the period of a simple pendulum primarily dependent on (for small oscillations)?

  1. Its length and the local gravitational acceleration g Correct answer.
  2. Only the mass of the pendulum bob
  3. Only the amplitude of the swing, regardless of length
  4. The color of the pendulum bob

Explanation

For small oscillations, a simple pendulum's period T = 2π√(L/g) depends on its length L and gravitational acceleration g, not on the bob's mass.

Question 9Mechanics

What is the relationship between frequency f and period T of an oscillation?

  1. f = 1/T Correct answer.
  2. f = T
  3. f = T^2
  4. f = 0, always

Explanation

Frequency is the reciprocal of the period: f = 1/T, where T is the time for one complete oscillation.

Question 10Mechanics

A wave has a wavelength of 2 m and travels at 340 m/s. What is its frequency?

  1. 170 Hz Correct answer.
  2. 680 Hz
  3. 0.0059 Hz
  4. 342 Hz

Explanation

Using v = f x λ, f = v / λ = 340 / 2 = 170 Hz.

Question 11Mechanics

What distinguishes a transverse wave from a longitudinal wave?

  1. In a transverse wave, particle oscillation is perpendicular to wave propagation; in a longitudinal wave, it is parallel Correct answer.
  2. Both wave types oscillate in exactly the same direction as propagation
  3. Transverse waves cannot travel through any medium
  4. Longitudinal waves have no measurable frequency

Explanation

Transverse waves (e.g. light, waves on a string) oscillate perpendicular to the direction of travel, while longitudinal waves (e.g. sound) oscillate parallel to the direction of travel.

Question 12Mechanics

What does the work-energy theorem state?

  1. The net work done on an object equals its change in kinetic energy Correct answer.
  2. Work is always equal to zero in any real process
  3. Energy can never be transformed from one form to another
  4. Work depends only on time, not on force or displacement

Explanation

The work-energy theorem states that the net work done on an object equals the change in its kinetic energy (W = ΔEkin).

Question 13Mechanics

An object is lifted 5 m against gravity, gaining gravitational potential energy. Using Epot = mgh with m = 2 kg and g = 9.81 m/s^2, what is its potential energy gain?

  1. 98.1 J Correct answer.
  2. 19.62 J
  3. 49.05 J
  4. 9.81 J

Explanation

Epot = m x g x h = 2 x 9.81 x 5 = 98.1 J.

Question 14Mechanics

According to the conservation of mechanical energy (ignoring friction), what happens to kinetic energy as an object falls and loses height?

  1. Kinetic energy increases as potential energy decreases by an equal amount Correct answer.
  2. Kinetic energy decreases as the object falls
  3. Both kinetic and potential energy increase simultaneously
  4. Total mechanical energy is not conserved in free fall

Explanation

As an object falls, its potential energy converts into kinetic energy, so kinetic energy increases while potential energy decreases by the same amount, keeping total mechanical energy constant (absent friction/air resistance).

Question 15Mechanics

An object undergoes uniformly accelerated motion from rest. Using s = 0.5 x a x t^2, if a = 2 m/s^2 and t = 4 s, what distance does it travel?

  1. 16 m Correct answer.
  2. 8 m
  3. 32 m
  4. 4 m

Explanation

s = 0.5 x a x t^2 = 0.5 x 2 x 16 = 16 m.

Question 16Mechanics

What is the SI unit of energy?

  1. Joule (J) Correct answer.
  2. Newton (N)
  3. Ampere (A)
  4. Ohm (Ω)

Explanation

The SI unit of energy (and work) is the Joule (J), defined as 1 kg·m^2/s^2, or equivalently 1 N·m.

Question 17Mechanics

What does 'power' (Leistung) measure in physics?

  1. The rate at which work is done or energy is transferred, measured in Watts Correct answer.
  2. The total amount of energy stored in an object
  3. The force applied to an object regardless of time
  4. The distance an object travels

Explanation

Power is defined as the rate of doing work or transferring energy (P = W/t), measured in Watts (1 W = 1 J/s).

Question 18Mechanics

In an elastic collision between two objects, what quantity is conserved in addition to momentum?

  1. Total kinetic energy Correct answer.
  2. Total mass is doubled
  3. Total charge is created from nothing
  4. Nothing else is conserved besides momentum

Explanation

In an elastic collision, both momentum and total kinetic energy are conserved, distinguishing it from an inelastic collision, where kinetic energy is not conserved (though momentum still is).

Question 19Mechanics

In a perfectly inelastic collision, what happens to the two colliding objects?

  1. They stick together and move with a common final velocity after the collision Correct answer.
  2. They bounce apart with no loss of kinetic energy
  3. They pass through each other completely unaffected
  4. They exchange all their mass with each other

Explanation

In a perfectly inelastic collision, the colliding objects stick together and move with a shared common velocity afterward, with kinetic energy not conserved (though momentum still is).

Question 20Mechanics

Why is it important for students to correctly identify units (e.g. N, J, W, C) in a physics calculation task?

  1. Because unit consistency verifies whether a calculated formula/result is dimensionally correct Correct answer.
  2. Units have no bearing on whether an answer is physically meaningful
  3. Only the numeric value matters; units can always be ignored
  4. Units are purely decorative labels with no verification function

Explanation

Checking that units are dimensionally consistent throughout a calculation is a standard way to catch errors and verify that a derived formula or numerical answer is physically sensible.

Question 21Mechanics

What does a velocity-time graph's slope represent?

  1. Acceleration Correct answer.
  2. Displacement
  3. Momentum
  4. Kinetic energy

Explanation

The slope of a velocity-time graph represents acceleration, since acceleration is the rate of change of velocity with respect to time.

Question 22Mechanics

What does the area under a velocity-time graph represent?

  1. Displacement (distance traveled in a given direction) Correct answer.
  2. Acceleration
  3. Force
  4. Power

Explanation

The area under a velocity-time graph equals the displacement over that time interval, since displacement is the integral of velocity over time.

Question 23Mechanics

Why is it useful to draw a free-body diagram (Kräftediagramm) before solving a Newtonian mechanics problem?

  1. It visually organizes all forces acting on an object, helping ensure none are omitted or misapplied in F = ma calculations Correct answer.
  2. It is purely an artistic exercise with no calculational benefit
  3. It replaces the need for any actual numeric calculation
  4. It only applies to problems involving electric charges, not mechanics

Explanation

A free-body diagram helps systematically identify and organize every force acting on an object, reducing the risk of missing a force or making a sign error before applying Newton's second law.

Question 24Mechanics

What is the difference between mass and weight in physics?

  1. Mass is an intrinsic amount of matter (kg); weight is the gravitational force on that mass (N), which varies with local gravity Correct answer.
  2. Mass and weight are identical in all cases and interchangeable terms
  3. Weight is measured in kilograms, and mass is measured in Newtons
  4. Mass changes depending on location, while weight never does

Explanation

Mass is a fixed, intrinsic property of an object (measured in kg), while weight is the gravitational force acting on that mass (measured in Newtons), which depends on local gravitational acceleration and thus varies by location (e.g. Earth vs. Moon).

Question 25Mechanics

What is the primary purpose of error analysis (Fehlerbetrachtung) in a physics experiment write-up?

  1. To assess the reliability and precision of measured results and identify sources of systematic or random error Correct answer.
  2. To make the experiment sound more impressive with no real analytical value
  3. To replace the need for actually performing the experiment
  4. To ensure results always exactly match textbook theoretical values

Explanation

Error analysis critically evaluates measurement precision and identifies systematic or random sources of error, a core scientific practice reflected in NRW Physik lab-based tasks.

Question 26Modern Physics

What is radioactive decay?

  1. The spontaneous transformation of an unstable atomic nucleus, releasing radiation and/or particles Correct answer.
  2. A chemical reaction between two stable molecules
  3. A process that only occurs when triggered by an external electric field
  4. A process that can be fully predicted for any single individual atom's exact decay moment

Explanation

Radioactive decay is the spontaneous transformation of an unstable nucleus into a more stable configuration, releasing radiation (alpha, beta, or gamma) in the process.

Question 27Modern Physics

What is emitted during alpha decay?

  1. A helium nucleus (2 protons and 2 neutrons) Correct answer.
  2. A high-energy electron
  3. A photon only, with no particle emission
  4. A neutrino only

Explanation

Alpha decay emits an alpha particle, which is a helium nucleus consisting of 2 protons and 2 neutrons, reducing the parent nucleus's mass number by 4 and atomic number by 2.

Question 28Modern Physics

What happens to a nucleus during beta-minus decay?

  1. A neutron converts into a proton, emitting an electron and an antineutrino Correct answer.
  2. A proton converts into a neutron, emitting a positron
  3. The nucleus emits a helium nucleus
  4. No change occurs to the nucleus's composition

Explanation

In beta-minus decay, a neutron within the nucleus converts into a proton, emitting a high-energy electron (beta particle) and an antineutrino, increasing the atomic number by 1.

Question 29Modern Physics

What is the half-life (Halbwertszeit) of a radioactive isotope?

  1. The time required for half of a sample's radioactive nuclei to decay Correct answer.
  2. The total time for an entire sample to fully decay to zero
  3. A fixed universal constant identical for every isotope
  4. The time required for a sample's mass to double

Explanation

Half-life is the characteristic time it takes for half of the radioactive nuclei in a sample to decay, a value specific to each isotope.

Question 30Modern Physics

A radioactive sample has a half-life of 8 days. Starting with 80 g, how much remains after 24 days?

  1. 10 g Correct answer.
  2. 40 g
  3. 20 g
  4. 0 g

Explanation

24 days is 3 half-lives (24/8 = 3). Remaining mass = 80 x (1/2)^3 = 80 x 1/8 = 10 g.

Question 31Modern Physics

What is nuclear binding energy?

  1. The energy required to separate a nucleus into its individual protons and neutrons Correct answer.
  2. The kinetic energy of an electron orbiting the nucleus
  3. The energy released only during chemical bond formation
  4. The total mass of the nucleus

Explanation

Nuclear binding energy is the energy that would be required to completely separate a nucleus into its constituent protons and neutrons, reflecting the mass defect via E = mc^2.

Question 32Modern Physics

What does Einstein's mass-energy equivalence formula E = mc^2 express?

  1. Mass and energy are equivalent and interconvertible, related by the speed of light squared Correct answer.
  2. Energy is completely unrelated to mass in any physical process
  3. Only light itself (photons) can have mass
  4. Mass always increases without bound as an object slows down

Explanation

E = mc^2 expresses that mass and energy are two forms of the same underlying physical quantity, interconvertible via the constant c^2, foundational to nuclear binding energy and relativistic physics.

Question 33Modern Physics

What is the mass defect in a nuclear reaction?

  1. The difference between the mass of the separated nucleons and the mass of the bound nucleus Correct answer.
  2. The mass of an electron alone
  3. A measurement error that should always be ignored
  4. The total charge of the nucleus

Explanation

The mass defect is the small difference between the sum of the masses of individual protons/neutrons and the actual (slightly lower) mass of the bound nucleus, which corresponds to the binding energy via E = mc^2.

Question 34Modern Physics

What is nuclear fission (Kernspaltung)?

  1. A heavy nucleus splits into two or more lighter nuclei, releasing energy Correct answer.
  2. Two light nuclei combine into a single heavier nucleus
  3. A nucleus emits only a photon with no change in composition
  4. A nucleus captures an electron with no other effect

Explanation

Nuclear fission occurs when a heavy nucleus (e.g. uranium-235) splits into two or more lighter nuclei, typically releasing neutrons and significant energy, as used in nuclear reactors.

Question 35Modern Physics

What is nuclear fusion?

  1. Two light nuclei combine to form a heavier nucleus, releasing energy (e.g. powering the Sun) Correct answer.
  2. A heavy nucleus splits into lighter fragments
  3. A process only relevant to chemical reactions
  4. A process that absorbs, rather than releases, energy in stars

Explanation

Nuclear fusion combines light nuclei (e.g. hydrogen isotopes) into heavier nuclei, releasing large amounts of energy - the process powering the Sun and other stars.

Question 36Modern Physics

What safety principle underlies radiation protection (Strahlenschutz), such as time, distance, and shielding?

  1. Minimizing exposure time, maximizing distance from the source, and using appropriate shielding material all reduce absorbed radiation dose Correct answer.
  2. Radiation exposure is always the same regardless of distance from the source
  3. Shielding has no measurable effect on radiation dose
  4. Radiation dose depends only on the color of protective clothing

Explanation

The classic Strahlenschutz principles - minimize time exposed, maximize distance (since intensity falls off with distance), and use shielding material appropriate to the radiation type - together reduce absorbed radiation dose.

Question 37Modern Physics

Which type of radiation (alpha, beta, or gamma) is typically stopped by just a sheet of paper?

  1. Alpha radiation Correct answer.
  2. Gamma radiation
  3. Neutron radiation
  4. No type of radiation can be stopped by paper

Explanation

Alpha particles, being relatively large and heavily charged, have low penetrating power and are typically stopped by a simple sheet of paper or a few centimeters of air.

Question 38Modern Physics

What safety precaution is standard when working with radioactive sources in a school physics lab?

  1. Using shielded, licensed low-activity sources, minimizing handling time, and following official radiation protection regulations Correct answer.
  2. Handling all radioactive sources with bare hands for as long as desired
  3. Ignoring all official safety regulations since school sources are assumed harmless
  4. Storing radioactive sources in any unlocked, publicly accessible location

Explanation

School use of radioactive sources is tightly regulated: low-activity, licensed sources are used with shielding, minimal handling time, and strict adherence to radiation protection regulations (Strahlenschutzverordnung).

Question 39Modern Physics

What is gamma radiation, in terms of its physical nature?

  1. High-energy electromagnetic radiation (photons) emitted from an unstable nucleus Correct answer.
  2. A stream of helium nuclei
  3. A stream of high-speed electrons
  4. A stream of neutrons exclusively

Explanation

Gamma radiation consists of high-energy electromagnetic photons emitted from a nucleus, often accompanying alpha or beta decay as the nucleus settles into a lower energy state.

Question 40Modern Physics

Why is gamma radiation the most penetrating of the three common radiation types (alpha, beta, gamma)?

  1. As uncharged, high-energy electromagnetic radiation, it interacts less readily with matter than the charged alpha and beta particles Correct answer.
  2. It has the largest mass of the three radiation types
  3. It travels slower than alpha or beta particles
  4. It is not actually more penetrating; alpha radiation penetrates furthest

Explanation

Because gamma rays are uncharged electromagnetic radiation, they interact less frequently with matter than the charged, more massive alpha and beta particles, allowing them to penetrate much further before being absorbed.

Question 41Modern Physics

A sample initially contains 1000 radioactive nuclei with a half-life of 10 minutes. Approximately how many remain after 20 minutes?

  1. 250 Correct answer.
  2. 500
  3. 125
  4. 1000

Explanation

20 minutes equals 2 half-lives (20/10 = 2). Remaining = 1000 x (1/2)^2 = 1000 x 1/4 = 250.

Question 42Modern Physics

What does the term 'Aktivität' (activity) of a radioactive sample measure?

  1. The number of nuclear decays occurring per unit time, measured in Becquerel (Bq) Correct answer.
  2. The total mass of the radioactive sample
  3. The exact identity of the daughter nuclide produced
  4. The color of the radiation emitted

Explanation

Activity measures the rate of radioactive decay events per unit time, expressed in Becquerel (1 Bq = 1 decay per second).

Question 43Modern Physics

What is the relationship between a radioactive sample's decay constant (λ) and its half-life (T½)?

  1. T½ = ln(2) / λ Correct answer.
  2. T½ = λ x 2
  3. T½ is completely unrelated to λ
  4. T½ = λ / ln(2)

Explanation

The half-life relates to the decay constant by T½ = ln(2)/λ, derived from the exponential decay law N(t) = N0 e^(-λt).

Question 44Modern Physics

What is a practical medical application of radioactive isotopes discussed in physics/chemistry curricula (e.g. Tc-99m)?

  1. Diagnostic imaging (nuclear medicine scans), using a short-half-life isotope's emitted radiation to visualize internal organs Correct answer.
  2. Permanently curing all diseases with no other treatment needed
  3. Replacing all forms of surgery entirely
  4. A purely theoretical use with no real medical application

Explanation

Isotopes like technetium-99m are widely used in nuclear medicine imaging, where their emitted gamma radiation helps visualize organ function, chosen partly for their convenient short half-life.

Question 45Electricity Magnetism

What is Coulomb's law used to calculate?

  1. The electrostatic force between two point charges Correct answer.
  2. The gravitational force between two planets
  3. The magnetic force on a moving charge only
  4. The kinetic energy of a falling object

Explanation

Coulomb's law, F = k(q1 q2)/r^2, calculates the electrostatic force between two point charges, analogous in form to Newton's gravitation law.

Question 46Electricity Magnetism

What defines the direction of an electric field at a point in space?

  1. The direction of the force that would act on a small positive test charge placed at that point Correct answer.
  2. The direction a negative charge would naturally repel toward
  3. A direction that is always perpendicular to any nearby magnetic field
  4. A direction that never changes regardless of the source charge arrangement

Explanation

By convention, electric field direction at a point is defined as the direction of the force on a small positive test charge placed there.

Question 47Electricity Magnetism

In a parallel-plate capacitor, the electric field between the plates is approximately what, in terms of voltage U and plate separation d?

  1. E = U / d Correct answer.
  2. E = U x d
  3. E = d / U
  4. E = U + d

Explanation

For a parallel-plate capacitor, the (approximately uniform) electric field between the plates is E = U/d, the voltage divided by the plate separation.

Question 48Electricity Magnetism

What force acts on a moving charged particle in a magnetic field, according to the Lorentz force concept?

  1. A force perpendicular to both the particle's velocity and the magnetic field direction Correct answer.
  2. A force always parallel to the particle's velocity
  3. No force at all if the particle is charged
  4. A force that depends only on the particle's mass, not its charge or velocity

Explanation

The magnetic component of the Lorentz force (F = qv x B) acts perpendicular to both the particle's velocity and the magnetic field, causing circular or helical motion rather than acceleration along the direction of travel.

Question 49Electricity Magnetism

Why does a charged particle moving perpendicular to a uniform magnetic field travel in a circular path?

  1. The magnetic force provides a constant centripetal force perpendicular to velocity, continuously changing direction but not speed Correct answer.
  2. The magnetic force accelerates the particle in a straight line
  3. The magnetic force has no effect on the particle's path at all
  4. The particle's charge is neutralized by the magnetic field

Explanation

Since the magnetic force is always perpendicular to velocity, it acts as a centripetal force that continuously changes the direction of motion (creating a circular path) without changing the particle's speed.

Question 50Electricity Magnetism

What is electromagnetic induction, as described by Faraday's law?

  1. A changing magnetic flux through a circuit induces an electromotive force (voltage) in that circuit Correct answer.
  2. A constant magnetic field always induces a large voltage
  3. Electric current can never create a magnetic field
  4. Induction only occurs in permanent magnets, never in coils

Explanation

Faraday's law of induction states that a changing magnetic flux through a conducting loop induces an electromotive force (EMF) in that loop.