Mechanics
Which quantity is given by the area under a velocity-time graph?
displacement
A force F was applied to compress a spring by a distance x.
A second spring of double the stiffness was compressed by the same distance x.
What is the magnitude, in terms of F, of the force applied to the second spring?
2F
A source of sound moved away from a stationary observer. The wavelength and frequency of the sound that reached the observer were compared to the wavelength and frequency of the sound emitted by the source when it was stationary. How does the observed frequency and wavelength changed when the source starts to move away?
frequency decreased, wavelength increased
An electron is accelerated through a large potential difference and gains a kinetic energy of 47 keV. This energy expressed as joules equals
7.5 x10-15 J
A potential difference of 600 mV is applied across a circuit component. What is the energy transferred when a charge of 2 C flows through the component?
1.2 J
A massive star exerts a gravitational force Fstar on a small distant planet. The planet exerts a gravitational force Fplanet on the star. How does the magnitude and direction of Fstar compare with Fplanet?
equal magnitude but opposite in direction
A stress σ is applied across the ends of a wire of cross-sectional area A.
Work W is done to extend the wire by ∆x.
Which expression, in terms of σ, A and ∆x, could be used to determine W?
W = 1/2 σA∆x
All the light from a source of power 15 W illuminates a surface area of 140 mm2. What is the radiation flux in Wm-2?
1.1 x105 Wm-2
The behaviour of light can be described in terms of waves or particles. State a phenomenon that demonstrate the particle nature of light.
Photoelectric effect or ejection of electrons in a metal surface by light
A sample of material has charge carrier density n and cross-sectional area A. When the current through the sample is I the drift velocity is v. Another sample of the same material has double the cross-sectional area and the current through it is 2I. What is the drift velocity?
v
An electric pump has an output power of 25 kW and an efficiency of 52%.
Which is the rate in kW at which energy is dissipated?
23 kW
A sample of a material is in the form of a wire. The material has a large value of the Young modulus. In terms of tensile stress and strain, what best describes this material?
the ratio between tensile stress and tensile strain is large
Light travels through air and enters a glass block.
What quantity does not change as the light enters the glass block?
frequency
The diagram shows some of the energy levels for a hydrogen atom. Which arrowed line, A, B, C or D, shows the transition of an electron that corresponds to the absorption of light with the shortest wavelength?
A
A student sets up the following circuit where X is an unknown component. The cell has negligible internal resistance. The student wants to produce a current-potential difference graph for component X. What change needs to be made to the circuit in order to collect the data?
add a variable resistor in series with the cell
A car travels north with a velocity of +50 ms−1. While still travelling north, the car slows to a velocity of +20 ms−1.
What is the change in velocity (magnitude and direction) of the car?
-30 ms-1
The flow of a fluid through a pipe is laminar. What correctly describes the velocity of the fluid?
The velocity is constant at a particular position.
A ray of light travels through glass, towards a boundary between glass and air. The critical angle for this boundary is 42°. At an incident angle of 45o, describe what will happen at the boundary between the glass and air?
there will be total internal reflection
When the surface of a metal is illuminated with a particular wavelength of light, electrons are emitted. What change in wavelength should happen so the ejection of electron stops?
increase the wavelength until it exceeds the threshold value
A student carries out an investigation to determine the e.m.f. ɛ and internal resistance r of a cell. The potential difference V across the cell and the current I in the cell are measured as the load resistance is increased. The results are plotted on a graph. From the graph, what describes the e.m.f. and the internal resistance?
y-intercept is the e.m.f. and the magnitude of gradient is the internal resistance
A ball bearing falls vertically from rest through a distance of 50 cm in a time of 0.32 s.
What expression gives the acceleration of the ball bearing in ms–2?
1 / 0.322
Which describes a situation, in terms of speed, size and shape, in which Stokes’ Law applies for objects moving in a fluid?
small spherical objects moving at low speeds
A string is stretched between two fixed points and set into oscillation. What quantity that describes the wave formed is the frequency of the vibrating string not dependent on?
amplitude
An energy level diagram for hydrogen, with four possible transitions between levels, is shown. Which transition will result in the emission of radiation of the shortest wavelength and what is the wavelength of the radiation emitted?
at A and the wavelength is 103 nm
A source of e.m.f. with no internal resistance is connected across a negative temperature coefficient thermistor. The current in the thermistor and the potential difference across the thermistor are measured. The temperature of the thermistor is increased. Describe the measured current and potential difference.
potential difference is unchanged, current increases