Cambridge IGCSE Physics - 0625 - Supplement Paper 4 2016 Summer Zone 1

(a) A bus travels at a constant speed. It stops for a short time and then travels at a higher constant speed.
Using the axes in Fig. 1.1, draw a distance-time graph for this bus journey. [3]
(b) A lift (elevator) starts from rest at the ground floor of a building.
Fig. 1.2 is the speed-time graph for the motion of the lift to the top floor of the building.
Use the graph to determine the distance from the ground floor to the top floor of the building.
distance = ......................................................... [4]

Fig. 2.1 shows a dummy of mass 70 kg used in a crash test to investigate the safety of a new car.


The car approaches a solid barrier at 20 m/s. It crashes into the barrier and stops suddenly.
(a) (i) Calculate the momentum of the dummy immediately before the crash.

momentum = ............................................................. [2]

(ii) Determine the impulse that must be applied to the dummy to bring it to rest.

impulse = ............................................................................ [1]

(b) In the crash test, the passenger compartment comes to rest in 0.20 s.
Calculate the deceleration of the passenger compartment.

deceleration = ............................................................. [2]

(c) The seat belt and air bag bring the dummy to rest so that it does not hit the windscreen.
The dummy has an average deceleration of 80 m/s^2.

Calculate the average resultant force applied to the dummy, of mass 70 kg.

force = ............................................................................... [2]

(d) The deceleration of the dummy is less than the deceleration of the passenger compartment.
Explain why this is of benefit for the safety of a passenger.
..................................................................................................................
..................................................................................................................
..................................................................................................................
..................................................................................................................
..................................................................................................................
.................................................................................................................. [2]

Fig. 3.1 shows an oil tank that has a rectangular base of dimensions 2.4 m by 1.5 m.



The tank is filled with oil of density $850 \text{ kg/m}^3$ to a depth of 1.5 m.

(a) Calculate

(i) the pressure exerted by the oil on the base of the tank,

pressure = ........................................................... [2]

(ii) the force exerted by the oil on the base of the tank.

force = ...................................................................... [2]

(b) The force calculated in (a)(ii) is the weight of the oil.

Calculate the mass of oil in the tank.

mass = ...................................................................... [1]

(c) When he is checking the level of oil in the tank, a man drops a brass key into the oil and it sinks to the bottom of the oil.

(i) State what this shows about the density of brass.
............................................................................................................................... [1]

(ii) Explain how attaching the key to a piece of wood could prevent the key from sinking.
...............................................................................................................................
...............................................................................................................................
............................................................................................................................... [1]

(a) Explain, in terms of molecules, why it is possible to compress a gas, but not a liquid.
.................................................................................................................
.................................................................................................................
.................................................................................................................
................................................................................................................. [2]

(b) Two containers made of insulating material contain the same volume of water at room temperature. The containers do not have lids. The volume of liquid in each container gradually decreases.

(i) After a certain time, the temperature of the water has decreased to below room temperature.

Explain, in terms of molecules, why the temperature has decreased.
.................................................................................................................
.................................................................................................................
.................................................................................................................
................................................................................................................. [2]

(ii) One of the containers is wide and shallow. The other container is narrow and deep.

Predict which container has the greater rate of cooling. Explain your answer.
.................................................................................................................
................................................................................................................. [2]

(a) State what happens to the molecules of a gas in a sealed container when the temperature of the gas is increased.
................................................................................................................................................................. [1]

(b) A quantity of gas is contained in a sealed container of fixed volume. The temperature of the gas is increased.

State, in terms of molecules, two reasons why the pressure of the gas increases.
1. ..................................................................................................................................................
2. .................................................................................................................................................. [2]

(c) A helium-filled weather balloon is held at ground level. The volume of the balloon is $$4800 ext{ m}^3$$. The pressure of the helium is 98 kPa.

The balloon is released and rises to a height where the volume of the balloon is $$7200 ext{ m}^3$$.

(i) Calculate the new pressure of the helium. Assume that the temperature stays constant.

pressure = ....................................................................... [2]

(ii) Suggest why it may be necessary to release helium from the balloon as it rises even higher.
................................................................................................................................................................
......................................................................................................................................................... [1]

(a) Two students are measuring the speed of sound. The students are provided with a starting pistol, a stopwatch and a long measuring tape. The starting pistol, when fired, produces a loud sound and a puff of smoke at the same instant. Describe how the students use the apparatus and how they calculate the speed. You may draw a diagram.

(b) A device at the bottom of the sea emits a sound wave of frequency 200 Hz.
(i) The speed of sound in sea-water is 1500 m/s. Calculate the wavelength of the sound in sea-water.
wavelength = \text{.........................................................} [2]

(ii) The sound wave passes from the sea-water into the air. State what happens, if anything, to
• the frequency of the sound, \text{.................................................................}
• the speed of the sound. \text{..........................................................} [2]

(a) (i) A ray of light passes through a length of curved optical fibre.
Draw a diagram showing the fibre and the path of the ray of light. [1]

(ii) Describe one use of optical fibres in medicine. You may draw a diagram.
.............................................................
.............................................................
.............................................................
.............................................................
.............................................................
............................................................. [3]

(b) Draw a straight line from each wave on the left to the most appropriate speed.
(() `light in air` (90 m/s (9 \times 10^1)), `microwaves in a vacuum` (6000 m/s (6 \times 10^3)), `sound in steel` (100000 m/s (1 \times 10^5)), `300000000 m/s (3 \times 10^8)`, `60000000000 m/s (6 \times 10^10)`) [3]

(c) The refractive index of a block of glass is 1.5.
Use your value for the speed of light from (b) to calculate the speed of light in this block.
speed = ............................................................. [2]

(a) Two straight, vertical wires X and Y pass through holes in a horizontal card.
Fig. 8.1 shows the card viewed from above.

There is a current in each wire in a downward direction (into the page).

(i) The magnetic field at Y due to the current in X produces a force on Y.
Place a tick in each blank column of the table to indicate the direction of this magnetic field and the direction of the force.

[Table_1]

(ii) State and explain whether there is also a force on wire X.
.......................................................................................................................................
....................................................................................................................................... [1]

(b) Fig. 8.2 shows a d.c. supply connected to the input of a transformer.

When switch S is first closed, the needle of the galvanometer deflects briefly, then returns to zero.
Explain why the brief deflection occurs.
.......................................................................................................................................
.......................................................................................................................................
.......................................................................................................................................
....................................................................................................................................... [3]

Fig. 9.1 shows a 12 V battery connected in a circuit containing resistors A, B, C, and D. Each resistor has a resistance of 6.0 Ω.



(a) Calculate the combined resistance of

(i) resistors A and B,

resistance = ............................................................. [1]

(ii) resistors A, B, and C,

resistance = ............................................................. [2]

(iii) resistors A, B, C, and D.

resistance = ............................................................. [1]

(b) Calculate

(i) the current in the battery,

current = ............................................................. [1]

(ii) the energy transferred from the battery to the circuit in 50s.

energy transferred = ............................................................. [2]

(a) (i) Fig. 10.1 shows the symbol for a circuit component.

Name this component.
.......................................................
[1]

(ii) In the space below, draw the symbol for a NOT gate.
[1]

(b) Fig. 10.2 shows a digital circuit.

Complete the truth table for this circuit.

Bismuth-214 is radioactive. It has a half-life of 20 minutes.
(a) The nuclide notation for bismuth-214 is $^{214}_{83}\text{Bi}$.
State the composition of the nucleus of bismuth-214.
..................................................................................................................
.................................................................................................................. [2]

(b) Bismuth-214 decays by $\beta$-decay to an isotope of polonium, Po.
Complete the equation for the decay of bismuth-214.
$$^{214}_{83}\text{Bi} \rightarrow \beta + \text{Po}$$ [3]

(c) The count rate from a sample of bismuth-214 is 360 counts/s.
Predict the count rate from the sample after 60 minutes.
count rate = .............................................................. [2]

(d) State two of the social, economic or environmental issues involved in the storage of radioactive materials with very long half-lives.
..................................................................................................................
..................................................................................................................
..................................................................................................................
.................................................................................................................. [2]