A
A ball is initially 50 m above the ground. The ball is thrown vertically upwards and takes 5.0 s to reach the ground. Air resistance is negligible.
What is the initial speed of the ball?
15 m/s
What is the resistance of an ideal voltmeter and the resistance of an ideal ammeter?
infinite and zero
The intensity of electromagnetic radiation incident on a surface is I. The wavelength of the radiation is doubled and the number of photons incident per unit time per unit area is doubled.
What is the new intensity of radiation incident on the surface?
I
Electric field lines
A. can cross each other.
B. are parallel to equipotential surfaces.
C. are directed from negative to positive charges.
D. show field strength by their density.
D
The moderator in a nuclear power station…
A. increases the proportion of U-235 in the fuel source.
B. transfers internal energy from the reactor to the turbines.
C. allows operators to regulate the rate of power production.
D. decreases the kinetic energy of neutrons in the reactor.
D
An object of mass 5.0 kg is initially at rest. An impulse of 2.0 N s acts on the object.
What is the final kinetic energy of the object?
0.4 J
A wire of length L is used in an electric heater. When the potential difference across the wire is 200 V, the power transferred in the wire is 500 W. A second wire is made from the same metal and has the same cross-sectional area. When a potential difference of 400 V is applied across the second wire, the power transferred is 2000 W.
What is the length of the second wire?
L
A train is sounding its whistle when approaching a train station. Three statements about the sound received by a stationary observer at the station are:
I. The frequency received is higher than the frequency emitted by the train.
II. The wavelength received is longer than the wavelength emitted by the train.
III. The speed of the sound received is not affected by the motion of the train.
Which combination of statements is correct?
I and III
A particle with charge Q is accelerated from rest through a potential difference V over a distance s.
The particle then enters a magnetic field of strength P at right angles to the magnetic field direction.
What single change will make the radius of curvature of the path of the particle smaller?
Increase P
A star has a parallax angle of 1 × 10−2 arc-second at the orbit of the Earth.
What is the distance from the Sun to the star?
100 pc
A spring obeys Hooke’s law and has a spring constant k .
The spring is extended horizontally. The extension of the spring is x.
When released, the spring returns to its original length in time t .
What is the average power developed by the spring as it returns to its original length?
kx2 /2t
The albedo of the atmosphere above a small region on the Earth’s surface is 0.25. The solar constant is S .
What is the incoming intensity of solar radiation incident on this region when the Sun is directly overhead?
3S/4
A pipe of length 0.75 m is closed at one end. The speed of sound of the air in the pipe is 330 m s−1.
What are the frequencies of the first two harmonics in the pipe?
110Hz and 330Hz
Planet X has a mass M and radius R with gravitational field strength g at its surface. Planet Y has mass 3M and radius 2R.
What is the gravitational field strength at the surface of planet Y?
3g/4
A nucleus of nuclide X decays.
Which series of emissions will produce an isotope of X?
A. One α and two β−
B. One α and two β+
C. Two α and two β−
D. Two α and two β+
A
A block of mass 2.0 kg is placed on a trolley of mass 5.0 kg, moving horizontally. A force of 8.0 N is applied to the block which slides on the surface of the trolley. The frictional force between the trolley and the ground is zero.
The trolley accelerates at a rate of 1.0 m /s2. What is the coefficient of dynamic friction between the block and the trolley?
0.25
A block of ice of mass M is at its melting point.
A smaller mass m of water at a temperature of T °C is placed on the top surface of the ice and remains there.
The specific latent heat of fusion of ice is L and the specific heat capacity of water is c.
What mass of ice melts?
mcT/L
A pendulum of length L oscillates with an angular frequency w. The mass of the pendulum is doubled and its length is changed to L/4 .
What is the new angular frequency of the pendulum?
2w
Four positive charges are fixed at the corners of a square that has a diagonal length of d. Three of the charges have a charge of Q .
The total electric potential at the centre of the square is 10kQ/d.
What is the magnitude of the fourth charge?
2Q
Electrons are accelerated through a potential difference and are incident on a sample of crystal atoms causing a diffraction pattern.
When the potential difference is increased, the maxima
A. are closer together.
B. are farther apart.
C. have a similar intensity.
D. are unchanged.
A. are closer together.
A spaceship leaves Earth and travels at a speed of 0.60c relative to the Earth to a point P.
P is 3.0 lightyears from Earth.
The spaceship then returns to Earth. Ignore the time taken to reverse the direction of the spaceship.
What is the time taken for the total journey to and from P as measured by an observer in the spaceship?
8 years
Energy is transferred very slowly to ice of mass 0.050 kg at its melting point so that the ice melts completely. The melted water remains at 0 °C.
The specific latent heat of fusion of ice = 335 kJ/kg
What is the entropy change of the ice?
0.061 kJ/K
Monochromatic light of wavelength λ is incident on a double slit. The resulting interference pattern is observed on a screen a distance y from the slits. The distance between consecutive fringes in the pattern is 55 mm when the slit separation is a.
λ, y and a are all doubled. What is the new distance between consecutive fringes?
110 mm
A horizontal conducting ring is perpendicular to a uniform vertical magnetic field. When the ring is rotated through 180° about the horizontal axis, an average emf of 2.0 μ V is induced in the ring. The area enclosed by the ring is 4.0 cm2 and the rotation takes 2.0 s.
What is the magnetic field?
5.0 mT
The Compton effect can be explained using
A. conservation of momentum
B. kinematic equations applied in two dimensions
C. the concept of a photon
D. the wave theory of light
A. conservation of momentum