AS & A Level Physics - 9702 Paper 1 2012 Summer Zone 2

What is the unit watt in terms of SI base units?

For which quantity is the magnitude a reasonable estimate?

A vector has magnitude $R$ and perpendicular components $P$ and $Q$, as shown in the diagram.

Which row correctly describes the perpendicular components?

The diameter of a cylindrical metal rod is measured using a micrometer screw gauge.

The diagram below shows an enlargement of the scale on the micrometer screw gauge when taking the measurement.

What is the cross-sectional area of the rod? 

A mass is dropped from rest, and falls through a distance of 2.0 m in a vacuum. An observer records the time taken for the mass to fall through this distance using a manually operated stopwatch and repeats the measurements a further two times. The average result of these measured times, displayed in the table below, was used to determine a value for the acceleration of free fall. This was calculated to be 9.8 m s\(^{-2}\).

Which statement best relates to the experiment? 

The diagram shows two complete pulses on the screen of a cathode-ray oscilloscope. A grid of 1 cm squares covers the screen. The time-base setting is 1 \mu s \text{ cm}^{-1}.

How long does each pulse last? 

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

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

Two markers $M_1$ and $M_2$ are set up a vertical distance $h$ apart.

A steel ball is released at time zero from a point a distance $x$ above $M_1$. The ball reaches $M_1$ at time $t_1$ and reaches $M_2$ at time $t_2$. The acceleration of the ball is constant.

Which expression gives the acceleration of the ball?

A brick is dislodged from a building and falls vertically under gravity.

Which graph best represents the variation of its height $h$ above the ground with time $t$ if air resistance is negligible?

A projectile is launched at point O and follows the path OPQRS, as shown. Air resistance may be neglected.

Which statement is true for the projectile when it is at the highest point Q of its path? 

Which row correctly states whether momentum and kinetic energy are conserved in an inelastic collision in which there are no external forces?

Two spheres approach each other along the same straight line. Their speeds are $u_1$ and $u_2$ before collision. After the collision, the spheres separate with speeds $v_1$ and $v_2$ in the directions shown below.

Which equation must be correct if the collision is perfectly elastic? 

A box of mass 8.0 kg rests on a horizontal, rough surface. A string attached to the box passes over a smooth pulley and supports a 2.0 kg mass at its other end.

When the box is released, a frictional force of 6.0 N acts on it.

What is the acceleration of the box? 

A ladder is positioned on icy (frictionless) ground and is leant against a rough wall. At the instant of release, it begins to slide.

Which diagram correctly shows the directions of the forces $P$, $W$ and $R$ acting on the ladder as it begins to slide?

The diagram shows a solid cube with weight $W$ and sides of length $L$. It is supported by a frictionless spindle that passes through the centres of two opposite vertical faces. One of these faces is shaded.

The spindle is now removed and replaced at a distance $\frac{L}{4}$ to the right of its original position.

When viewing the shaded face, what is the torque of the couple that will now be needed to stop the cube from toppling? 

A sphere is released from rest in a viscous fluid. Which graph represents the variation with time $t$ of the acceleration $a$ of the sphere? 

Initially, four identical uniform blocks, each of mass $m$ and thickness $h$, are spread on a table.

How much work is done on the blocks in stacking them on top of one another? 

The diagram shows the design of a water wheel which drives a generator to produce electrical energy. The flow rate of the water is 200$ kg  s^{-1}$. The generator supplies a current of 32 A at a voltage of 230 V.

Ignoring any changes in kinetic energy of the water, what is the efficiency of the system? 

A car engine exerts an average force of 500 N in moving the car 1.0 km in 200 s.

What is the average power developed by the engine?

A mass of gas enclosed in a cylinder by a piston is heated gently. At the same time, the piston is moved so that the pressure remains constant. As a result of this, what will not occur?

In an experiment to demonstrate Brownian motion, a transparent container is filled with smoke particles suspended in air.

What can be seen when the contents of the container are strongly illuminated and viewed through a microscope?

The diagram shows the arrangement of atoms in a particular crystal.

Each atom is at the corner of a cube.

The mass of each atom is $3.5 \times 10^{-25} \text{ kg}$. The density of the crystal is $9.2 \times 10^3 \text{ kg m}^{-3}$.

What is the shortest distance between the centres of two adjacent atoms?

A pipe is closed at one end and contains gas, trapped by a column of water.

The atmospheric pressure is $1.0 \times 10^5 \text{ Pa}$. The density of water is $1000 \text{ kg m}^{-3}$.

What is the pressure of the gas? (Use $g = 10 \text{ m s}^{-2}$.) 

The graph is a force-extension graph for a wire that is being stretched.

How much work needs to be done by the tensile force, to two significant figures, to cause an extension of 7.0 mm?

A wire stretches 8 mm under a load of 60 N.

A second wire of the same material, with half the diameter and a quarter of the original length of the first wire, is stretched by the same load.

Assuming that Hooke's law is obeyed, what is the extension of this wire?

A surveyor’s device emits a laser pulse.

What is the time taken for the pulse to travel from the device to a wall 150 m away, where it is reflected, and then return to the device?

The period of an electromagnetic wave is 1.0 ns.

What are the frequency and wavelength of the wave?

X and Y are two points on the surface of water in a ripple tank. A source of waves of constant frequency begins to generate waves which then travel past X and Y, causing them to oscillate.

What is the phase difference between X and Y?

A monochromatic plane wave of speed $c$ and wavelength $\lambda$ is diffracted at a small aperture.

The diagram illustrates successive wavefronts.

After what time will some portion of the wavefront XY reach point P?

A standing sound wave is set up between a loudspeaker and a wall.

A microphone is connected to a cathode-ray oscilloscope (c.r.o.) and is moved along a line directly between the loudspeaker and the wall. The amplitude of the trace on the c.r.o. rises to a maximum at a position X, falls to a minimum and then rises once again to a maximum at a position Y.

The distance between X and Y is 33 cm. The speed of sound in air is 330 m s^{-1}.

Which diagram represents the c.r.o. trace of the sound received at X?

An electric field exists in the space between two charged metal plates.

Which graph shows the variation of electric field strength $E$ with distance $d$ from $X$ along the line $XY$? 

When will 1 C of charge pass a point in an electrical circuit?

Two copper wires of the same length but different diameters carry the same current.
Which statement about the flow of charged particles through the wires is correct?

A power cable X has resistance $R$ and carries current $I$.
A second cable Y has resistance $2R$ and carries current $\frac{1}{2}I$.
What is the ratio $$\frac{\text{power dissipated in Y}}{\text{power dissipated in X}}$$?

The diagram shows a circuit with four voltmeter readings $V$, $V_1$, $V_2$, and $V_3$.

Which equation relating the voltmeter readings must be true?

A light-dependent resistor (LDR) is connected in series with a resistor R and a battery.

The resistance of the LDR is equal to the resistance of R when no light falls on the LDR.
When the light intensity falling on the LDR increases, which statement is correct?

The diagram shows the circuit for a signal to display a green or a red light. It is controlled by the switch S.

The signal is some way from S to which it is connected by a cable with green, red and black wires. At the signal, the green and red wires are connected to the corresponding lamp and the black wire is connected to a terminal x to provide a common return. The arrangement is shown correctly connected and with the switch set to illuminate the red lamp.
During maintenance, the wires at the signal are disconnected and, when reconnected, the black wire is connected in error to the green lamp (terminal g) instead of terminal x. The red wire is connected correctly to its lamp and connections at S remain as in the diagram.

When the system is tested with the switch connection to the red wire, what does the signal show?

Four identical resistors are connected in the three networks below. Which arrangement has the highest total resistance and which has the lowest?

Nuclear decay is both spontaneous and random in nature. Which row gives the correct experimental evidence for these properties? [Table_1]

Radon $^{222}_{86}\text{Rn}$ is the start of a decay chain that forms bismuth $^{214}_{83}\text{Bi}$ by alpha and beta emission. For the decay of each nucleus of radon, how many $\alpha$-particles and $\beta$-particles are emitted? [Table_1]