Variant 2 Feb/Mar 2016

1. To mark a temperature scale on a thermometer, standard temperatures known as fixed points are needed.
Which of these is a fixed point on the Celsius scale?

2. A sound wave travels from a point X to a point Y.

Which diagram represents the movement of the air molecules, due to the sound wave, in the region between X and Y?

3. The table describes four different resistance wires. They are all made from the same metal.
Which wire has the smallest resistance?

4. The diagram shows a potential divider connected to two voltmeters P and Q.

The resistance of the variable resistor is decreased.
Which row shows what happens to the reading on each voltmeter?

5. One end of a copper rod is heated.
What is one method by which thermal energy is transferred in the copper rod?

6. A force acts on an area to produce a pressure.
Which changes produce the same pressure?

7. The diagram shows a cuboid block made from a metal of density 2.5g/ cm³.

What is the mass of the block?

8. The diagram shows an a.c. generator.

As the coil passes through the position shown, the output voltage is +10 V.
When does the output voltage become –10 V?

9. Which methods could be used to demagnetise a magnet?

method 1: place it in an east-west direction and hammer it
method 2: place it in an east-west direction and heat it until it is red hot
method 3: pull it slowly from a coil that is carrying an alternating current
method 4: put it slowly into a coil that is carrying a direct current

10. A spring obeys Hooke’s law.
Which graph is obtained by plotting the extension of the spring against the load applied?

11. The table gives four energy sources and states whether the energy of the source is derived from the Sun.
Which row is correct?

12. The diagram shows an object moving at a constant speed in a circular path in the direction shown.
A force acts on the object to keep it in the circular path.
In which labelled direction does this force act, when the object is in the position shown?

13. The speed of sound in air is 340m/ s.
Which row gives typical values for the speed of sound in a liquid and in a solid?

14. A scientist carries out an experiment using a sealed source which emits β-particles. The range of the β-particles in the air is about 30cm.
Which precaution is the most effective to protect the scientist from the radiation?

15. Which quantity gives the thermal capacity of a solid object?

16. An electron moves into a uniform magnetic field.
The arrow shows the initial direction of motion of the electron.
The direction of the magnetic field is into the plane of the page (away from you).

In which direction does a force act on the electron when it enters the magnetic field?

17. A wind turbine generates 54kW of useful power from an input of 180kW of wind power.
Which calculation gives the percentage efficiency of the turbine?

18. Two plastic cups are placed one inside the other. A small spacer keeps the two cups separated.
Hot water is poured into the inner cup and a lid is put on top, as shown.

Which statement is correct?

19. After some building work in a house, a bare (uninsulated) live wire is left protruding from a wall.
What is the greatest hazard?

20. In an experiment, a liquid is heated at a constant rate.
The temperature of the liquid increases and eventually becomes constant.
Which statement about the experiment is correct?

21. Which is a unit of acceleration?

22. Gases can be compressed, but liquids cannot.

Which statement explains this difference?

23. In which pair are both materials magnetic?

24. A battery charger plugs into a 230 V a.c. supply. The charger is used to charge a 6.0 V d.c. battery.
The charger contains diodes and a transformer.
What is the purpose of these components?

25. The scattering of α-particles by a thin metal foil supports the nuclear model of an atom.
Why are α-particles used rather than neutrons?

26. The diameter of a copper wire is thought to be approximately 0.3mm.
Which instrument should be used to obtain a more accurate measurement of the diameter of the wire?

27. A nucleus of a radioactive substance 218/84 Po undergoes an α-decay followed by a β-decay.
What are the nucleon (mass) number and proton (atomic) number of the nuclide formed after both decays have happened?

28. Which row describes the nature of α-particles and of γ-rays?

29. Which diagram shows how a converging lens is used as a magnifying glass?

30. A weight-lifter raises a 2000N weight through a vertical height of 2.0m in 0.80s.What useful power does he develop in doing this?

31. A concrete post is carried up a very high mountain. At the top of the mountain, the gravitational field is slightly weaker than at the bottom.
What is the effect of this weaker field on the mass and on the weight of the post at the top of the mountain?

32. Four lamps are each labelled 240V.
In which circuit do all four lamps have normal brightness?

33. Which diagram correctly shows a ray of light reflected by a plane mirror?

34. Which circuit shows the directions of the conventional current I and the flow of electrons?

35. Which is the value of a vector quantity?

36. Which produces an electromotive force (e.m.f.)?

37. An object is released from rest and falls to Earth. During its fall, the object is affected by air
resistance. The air resistance eventually reaches a constant value.

Which description about successive stages of the motion of the object is correct?

38. Which is a unit of wavelength?

39. The diagram shows a quantity of gas trapped in a cylinder. The piston is pushed in slowly and the gas is compressed. The temperature of the gas does not change.

Which graph shows the relationship between the pressure and the volume of the gas?

40. Identical toy bricks are placed one on top of another to make a tower on a table.

Which graph shows the relationship between the pressure P that the tower exerts on the table and the weight W of the tower?