Topic A: Space, Time, Motion
A particle moves in a straight line. At one instant, its velocity is zero but its acceleration is non-zero. Which situation could produce this?
A. A particle moving at constant velocity
B. A particle at the highest point of its vertical motion
C. A particle moving at constant speed in a straight line
D. A particle that has never moved
B. A particle at the highest point of its vertical motion
Which process is primarily responsible for the natural greenhouse effect?
A. Greenhouse gases absorb incoming visible light from the Sun.
B. Greenhouse gases absorb and re-emit outgoing infrared radiation from Earth's surface.
C. Clouds reflect all infrared radiation back toward Earth.
D. Oxygen absorbs most of the radiation emitted by Earth's surface.
B. Greenhouse gases absorb and re-emit outgoing infrared radiation from Earth's surface.
A wave travels from one medium into another. Which property of the wave is determined by the source and therefore remains unchanged?
A. Speed
B. Wavelength
C. Frequency
D. Amplitude
C. Frequency
A uniform rigid object is in rotational equilibrium. Which statement must be true?
A. The net force is zero only.
B. The net torque is zero only.
C. Both the net force and net torque are zero.
D. The angular velocity must be zero.
C. Both the net force and net torque are zero.
Which quantity is a vector?
A. Distance
B. Speed
C. Mass
D. Velocity
D. Velocity
A particle has a constant negative acceleration. Which statement must be true?
A. Its velocity is negative.
B. Its speed is decreasing.
C. Its velocity is becoming increasingly negative.
D. It is moving in the negative direction.
C. Its velocity is becoming increasingly negative.
A gas is compressed while its temperature remains constant. Which statement is correct?
A. The average kinetic energy of the particles increases.
B. The average kinetic energy of the particles decreases.
C. The pressure increases because particles collide with the container walls more frequently.
D. The pressure decreases because the particles have less space to move.
C. The pressure increases because particles collide with the container walls more frequently.
Two waves have the same frequency and wavelength but different amplitudes. Which statement is correct?
A. They must travel at different speeds.
B. They have different frequencies.
C. They carry different amounts of energy.
D. They must be travelling in different media.
C. They carry different amounts of energy.
A spacecraft travels at a speed close to the speed of light relative to Earth. An observer on Earth measures the spacecraft's clock. Compared with a clock at rest on Earth, the spacecraft's clock is observed to:
A. Run faster
B. Run at the same rate
C. Run slower
D. Stop completely
C. Run slower
A car travels around a circular track at constant speed. Which statement is correct?
A. Its velocity is constant
B. Its acceleration is zero
C. Its velocity changes continuously
D. Its acceleration is parallel to its velocity
C. Its velocity changes continuously
An object travels in a straight line. Its velocity changes from +8m s−1 to +2m s−1. Which statement is true, assuming a constant acceleration?
A. The object has negative displacement.
B. The object has negative acceleration during the entire interval.
C. The object has negative velocity during the entire interval.
D. The object has zero acceleration at some point.
B. The object has negative acceleration during the entire interval.
Which statement is consistent with the first law of thermodynamics?
A. Energy can be created if work is done on a system.
B. Energy can be destroyed when a system loses thermal energy.
C. The change in internal energy depends on energy transferred as heat and work.
D. Internal energy is always equal to the thermal energy transferred to a system.
C. The change in internal energy depends on energy transferred as heat and work.
A wave travels from a deep region of water into a shallow region. Its speed decreases. Which change occurs?
A. Frequency decreases and wavelength remains constant.
B. Frequency remains constant and wavelength decreases.
C. Frequency increases and wavelength decreases.
D. Frequency remains constant and wavelength increases.
B. Frequency remains constant and wavelength decreases.
An ideal gas undergoes an isothermal expansion. Which statement correctly describes the process?
A. The internal energy increases because the gas does work.
B. The internal energy decreases because the gas does work.
C. The internal energy remains constant because no work is done.
D. The internal energy remains constant because the temperature remains constant.
D. The internal energy remains constant because the temperature remains constant.
Two objects have the same momentum but different masses. Which object has the greater speed?
A. The more massive object
B. The less massive object
C. Both have the same speed
D. It cannot be determined
B. The less massive object
Two objects, A and B, start from the same position at the same time. Their velocity–time graphs intersect at t=5s. What can be concluded at this instant?
A. They have the same acceleration.
B. They have travelled the same distance.
C. They have the same velocity.
D. They have the same displacement.
C. They have the same velocity.
A real battery is connected to an external resistor. As the current drawn from the battery increases, the terminal potential difference decreases. Which explanation is most appropriate?
A. The battery's emf decreases because electrons move faster.
B. The internal resistance of the battery causes a greater potential drop inside the battery as current increases.
C. The external resistance automatically increases.
D. Charge is being destroyed inside the battery.
B. The internal resistance of the battery causes a greater potential drop inside the battery as current increases.
In a double-slit experiment, the wavelength of the waves is increased while the slit separation and screen distance remain constant. What happens to the separation between adjacent interference maxima?
A. It increases
B. It decreases
C. It remains unchanged
D. The maxima disappear
A. It increases
A source of sound moves toward a stationary observer at constant velocity. The observer measures a higher frequency than the frequency emitted by the source. Which explanation is most accurate?
A. The source produces sound waves with a greater intrinsic frequency as it approaches the observer.
B. The wave speed increases because the source is moving toward the observer.
C. The wavefronts become closer together in the direction of motion, reducing the observed wavelength while the wave speed in the medium remains approximately constant.
D. The amplitude of the sound increases, causing the observed frequency to increase.
C. The wavefronts become closer together in the direction of motion, reducing the observed wavelength while the wave speed in the medium remains approximately constant.
A gas undergoes a cyclic process and returns to its original state. Which statement must be true for the complete cycle?
A. Net work is zero
B. Net energy transfer by heating is zero
C. Change in internal energy is zero
D. Pressure remains constant throughout
C. Change in internal energy is zero
Two particles have identical velocity–time graphs between t=0 and t=10s, except that particle B's graph is shifted vertically upward by 5m s−1.
Which statement is correct?
A. They have identical displacements.
B. They have identical accelerations but different displacements.
C. They have different accelerations and identical displacements.
D. Particle B has both greater acceleration and greater displacement.
B. They have identical accelerations but different displacements.
A planet receives a constant amount of energy from its star. Its atmosphere becomes more effective at absorbing outgoing infrared radiation.
Which statement best describes the initial and eventual response?
A. The planet immediately receives more energy from its star.
B.The planet's temperature decreases because less infrared radiation reaches its surface.
C. The planet eventually reaches absolute zero because infrared radiation cannot escape.
D. The planet initially loses energy to space at a slower rate, causing its temperature to increase until a new radiative equilibrium is established.
D. The planet initially loses energy to space at a slower rate, causing its temperature to increase until a new radiative equilibrium is established.
Two coherent waves reach a point with a path difference of exactly λ/2. Which outcome is expected?
A. Constructive interference because the waves are in phase.
B. Destructive interference because the waves arrive 180∘ out of phase.
C. No interference because the path difference is non-zero.
D. Constructive interference because the path difference is less than one wavelength.
B. Destructive interference because the waves arrive 180∘ out of phase.
A spaceship travels at a constant speed relative to Earth. A light pulse is emitted from the center of the spaceship toward its front and another pulse toward its rear simultaneously according to an observer inside the spaceship.
An observer on Earth measures the two events. Which statement is correct?
A. The Earth observer can determine that the pulses do not reach the front and rear simultaneously, because simultaneity depends on the reference frame.
B. The pulses reach the front and rear simultaneously because simultaneity is absolute.
C. The pulses reach the front and rear simultaneously because light has the same speed for all observers.
D. The Earth observer measures different speeds for the two light pulses.
A. The Earth observer can determine that the pulses do not reach the front and rear simultaneously, because simultaneity depends on the reference frame.
Two coherent sources produce waves of wavelength λ. At a point, the path difference is 3λ/2. What is observed?
A. Constructive interference
B. Destructive interference
C. No interference
D. Complete reflection
B. Destructive interference