AS & A Level Physics - 9702 Paper 1 2016 Summer Zone 2

Which quantity with its unit is correct?

The luminosity $L$ of a star is given by

$L = 4\pi r^2 \sigma T^4$

where

$r$ is the radius of the star,

$T$ is the temperature of the star,

$\sigma$ is a constant with units $W \text{m}^{-2} \text{K}^{-4}$.

What are the SI base units of $L$?

The diagram shows two vectors X and Y, drawn to scale.
If X = Y − Z, which diagram best represents the vector Z?

The diagram shows a cathode-ray oscilloscope (c.r.o.) being used to measure the rate of rotation of a flywheel.
The flywheel has a small magnet M mounted on it. Each time the magnet passes the coil, a voltage pulse is generated, which is passed to the c.r.o. The display of the c.r.o. is 10 cm wide. The flywheel is rotating at 3000 revolutions per minute.
Which time-base setting will display clearly separate pulses on the screen?

A student determines the density $\rho$ of steel by taking measurements from a steel wire.
mass $m = 6.2 \pm 0.1 \text{ g}$
length $l = 25.0 \pm 0.1 \text{ cm}$
diameter $d = 2.00 \pm 0.01 \text{ mm}$
He uses the equation $\rho = \frac{4m}{\pi d^2 l}$.
What is the percentage uncertainty in his calculated value of density?

The acceleration of free fall on the Moon is $1.6 \, \text{m}\,\text{s}^{-2}$. The Moon has no atmosphere. An astronaut standing on the surface of the Moon drops a feather.

Which graph shows the variation with time of the speed of the feather during the first second of its fall? 

A tennis ball is released from rest at the top of a tall building. Which graph best represents the variation with time $t$ of the acceleration $a$ of the ball as it falls, assuming that the effect of air resistance is not negligible?

The graph shows how the velocity $v$ of an object moving in a straight line varies with time $t$ from $t = 0$ to $t = T$.

Which graph represents the displacement $s$ of the object in the time $t = 0$ to $t = T$? 

A ball falls vertically onto horizontal ground and rebounds, as shown.

The ball has momentum $p_1$ downwards just before hitting the ground. After rebounding, the ball leaves the ground with momentum $p_2$ upwards. The ball is in contact with the ground for 0.020 s. During this time interval, an average resultant force of 25 N acts on the ball.

What is a possible combination of values for $p_1$ and $p_2$?

A sphere falls from rest through the air. The graph shows the variation with time of the sphere’s velocity.

Which diagram shows the forces acting on the sphere when it is at the velocity corresponding to point P on the graph? 

A ball of mass $m$ travelling at velocity $u$ collides with a stationary ball of mass $M$. After collision, the two balls travel at velocities $v$ and $V$ respectively, in the directions shown.

A student writes three equations relating to the collision.

Which row in the table indicates the correct and incorrect equations?

A light rigid rod XY has an object of weight $W$ fixed at one end. The rod is in equilibrium, resting on a roller at Z and a vertical wall at X. The roller exerts a force $R$ on the rod as shown. The diagram shows the directions, but not the magnitudes, of the forces $R$ and $W$.

What is the direction of the force on the rod at X? 

In a large container in an oil refinery, three oils of different densities are mixed. No chemical activity occurs.
The mixture consists of

• 1200 kg of oil of density $1100 \, \text{kg} \, \text{m}^{-3}$,
• 1500 kg of oil of density $860 \, \text{kg} \, \text{m}^{-3}$,
• 4000 kg of oil of density $910 \, \text{kg} \, \text{m}^{-3}$.

What is the density of the mixture?

Two coplanar forces act on the rim of a wheel. The forces are equal in magnitude.

Which arrangement of forces provides only a couple?

The density of air on the Earth decreases almost linearly with height from 1.22 $\text{kg m}^{-3}$ at sea level to 0.74 $\text{kg m}^{-3}$ at an altitude of 5000 m.

Atmospheric pressure at the Earth's surface on a particular day is 100000 Pa. The value of $g$ between the Earth's surface and an altitude of 5000 m can be considered to have a constant value of 9.7 $\text{m s}^{-2}$.

What will be the atmospheric pressure at an altitude of 5000 m?

A parachutist is falling at constant (terminal) velocity.

Which statement is not correct?

A boy on a bicycle starts from rest and rolls down a hill inclined at 30° to the horizontal. The boy and bicycle have a combined mass of 25 kg. There is a frictional force of 30 N, which is independent of the velocity of the bicycle. What is the kinetic energy of the boy and the bicycle after rolling 20 m down the slope?

An escalator in an underground station has 250 people standing on it and is moving with a velocity of 4.3 ms⁻¹. The average mass of a person is 78 kg and the angle of the escalator to the horizontal is 40°. What is the minimum power required to lift these people?

An electric motor operating a lift has an output power of 20 kW.

The lift and passengers have a combined mass of 1500 kg. The motor raises the lift through a distance of 20 m.
How long does it take? 

A spring balance consists of a spring of length 20.0 cm with a hook attached. When a fish of mass 3.0 kg is suspended from the hook, the new length of the spring is 27.0 cm. What is the spring constant of the spring?

A metal wire is attached at one end to a fixed point and a load is hung from the other end so that the wire hangs vertically. The load is increased from zero to 20 N. This causes the wire to extend elastically by 5.0 mm. The load is then reduced to 12 N and the extension decreases to 3.0 mm.

How much strain energy is released during the unloading process? 

A microphone connected to the Y-plates of a cathode-ray oscilloscope (c.r.o.) is placed in front of a loudspeaker. The trace on the screen of the c.r.o. is shown.

The time-base setting is 0.5 ms cm^-1 and the Y-plate sensitivity is 0.2 mV cm^-1.

What is the frequency of the sound from the loudspeaker and what is the amplitude of the trace on the c.r.o.? 

A source of sound of frequency 1000 Hz moves away from a stationary observer at a speed of 30.0 m s$^{-1}$. The speed of sound is 330 m s$^{-1}$.

What is the frequency of the sound heard by the observer?

Each of the principal radiations of the electromagnetic spectrum has a range of wavelengths.

Which wavelength is correctly linked to its radiation?

A stationary wave is set up on a stretched string.

The diagram shows the string at two instants of time when it has maximum displacement.

The oscillations of point P on the string have amplitude A.

What is the distance moved by P from the position shown in the diagram after half a time period of the wave?

Which statement is an example of the diffraction of light?

Sound waves of wavelength $\lambda$ are emitted by a loudspeaker and pass through two slits P and Q. Two sound waves from the slits meet at R.

What is the condition for an intensity maximum (loud sound) to be detected by a microphone at R?

Coherent light passes through a double slit, producing bright and dark fringes on a screen placed parallel to the plane of the double slit. The intensity of the light from each of the slits is initially the same.

The intensity of the light passing through one of the slits in the double slit is now increased. The frequency of the light remains constant.

What is the effect on the appearance of the fringes on the screen?

Which diagram shows the pattern of the electric field between a positively charged metal sphere and a negatively charged metal plate? 

Before a thunderstorm, the hairs on your head sometimes stand on end.

A hair with mass 0.50 mg and charge 1.0 pC is supported by a force due to an electric field.

Ignore any forces other than the weight of the hair and the electric force.

What is the electric field strength?

Two parallel metal plates, 4.0 cm apart, are at electric potentials of 800 V and 2000 V. Points X, Y and Z are situated in the space between the plates at distances of 1.0 cm, 2.0 cm and 3.0 cm from the lower plate.

What is the electric field strength, in V m$^{-1}$, at X, Y and Z? 

The potential difference $V$ across a filament lamp is slowly raised from zero to its normal operating value. Which graph represents the variation with $V$ of the current $I$ in the lamp?

Two lamps are connected in series to a 250V power supply. One lamp is rated 240V, 60W and the other is rated 10V, 2.5W.
Which statement most accurately describes what happens?

Which equation is used to define resistance?

The charge that a fully charged 12 V car battery can supply is 100 kC. The starter motor of the car requires a current of 200 A for an average period of 2.0 s. The battery does not recharge because of a fault.
What is the maximum number of times the starter motor of the car can be used?

A potential divider circuit is formed by connecting a battery of negligible internal resistance in series with two variable resistors, as shown.
The variable resistors have resistances $R_X$ and $R_Y$.
$V_X$ is the potential difference across resistance $R_X$.
$R_X$ and $R_Y$ are both changed at the same time.
Which combination of changes must cause $V_X$ to increase?

In the circuit shown, contact may be made at any point along the 3\(\Omega\) resistor (potentiometer). The battery has e.m.f. 9V and negligible internal resistance. What is the maximum range of the output voltage?

The gold nucleus $^{185}_{79}\text{Au}$ undergoes alpha decay. What are the nucleon number and proton number of the nucleus formed by this decay? [Table_1]

Which row gives the correct classification of protons, electrons and neutrinos? [Table_1]

Which equation represents $\beta^+$ decay?