(i) The centre of gravity G of a body can be defined as:
A.The centre of attraction of the earth
B.The focus of the solar system
C.The point through which the resultant of the weights of all particles of the body acts.
D.The point through which the lines of symmetry of a body passes.
8.10 marks
A camera has a lens of focal length 4cm. It is used;
(i) first for taking a photograph of an object a long distance away and then
(ii) for taking a photograph of an object 2.0m away from the camera.
(a)
How is the amount of light energy reaching the film of a camera controlled?
2 mk
(b)
Through what distance must the lens be moved and in what direction, in order to take the photograph in (ii)?
8 mk
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9.1 mark
An object placed infront of a diverging lens of focal length 0.15m produces an image at a distance of 0.10m from the lens. This implies that the distance of the object from the lens is:
A.0.3m
B.- 0.3m
C.0.06m
D.-0.06m
10.1 mark
Good emitters of heat energy are also:
A.good reflectors of heat
B.good transmitters of heat
C.good absorbers of heat
D.poor absorbers of heat.
11.1 mark
If the velocity of sound in a solid is 1.4 km/s, then a sound wave of frequency 700Hz has a wavelength of:
A.2.0m
B.0.2m
C.0.2km
D.2.0km.
12.1 mark
The zig-zag path traversed by electrons from a negatively charged cloud towards a positively charged one is called:
A.radar
B.lightning
C.thunder
D.field emission.
13.1 mark
An iron nail AB is inserted in a coil made of an insulated copper wire whose ends are connected to the terminals of a dry cell as shown in the figure here under:
The correct way of labelling the poles of the resulting electromagnet is:
A.A is N and B is S
B.A is S and B is N
C.A and B change alternately between N and S
D.A and B are both neutral points.
14.1 mark
The theory of astronomy which explains convincingly the occurrence of day and night and which is the basis of the solar system is:
A.The Geocentric theory
B.The law of gravitation
C.The heliocentric theory
D.The tectonic theory.
15.1 mark
The truth about X rays is that:
A.they can be deflected by both electric and magnetic fields
B.they are fast moving electrons
C.they are of very low frequency and very long wavelength
D.they are electromagnetic waves.
Section B
2.9 marks
SECTION B (45 MARKS)
Answer ALL the questions in this section. All working for each question attempted must be
shown clearly.
(a)
Explain the meaning of each of the terms:
Mass, Inertia and Impulse
3 mk
(b)
A bullet of mass 250g is fired from a gun of mass 5kg, exerting a force of 30N against the
gunman which persisted for 2 seconds. Find the velocities of the bullet and recoil of the
gun.
6 mk
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3.9 marks
SECTION B (45 MARKS)
Answer ALL the questions in this section. All working for each question attempted must be
shown clearly.
(a)
Describe a simple experiment to demonstrate that water and petrol have different thermal
expansivities.
5 mk
(b)
The volumes of a liquid at 15°C and 65°C are 6.0 x 10-5 m3 and 6.1x10-5m 3 respectively.
Find the apparent volume expansivity of the liquid.
4 mk
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4.9 marks
SECTION B (45 MARKS)
Answer ALL the questions in this section. All working for each question attempted must be
shown clearly.
(a)
Define the terms:
Ampere, Ohm, Resistance and Conductance as referred to in electricity
4 mk
(b)
Each of two new dry cells has an e.m.f. of 1.5 volts and internal resistance of 1.0 ohm.
The two cells are connected in parallel and the combination connected to a 10 ohm
resistor. Find the current and heat developed per second on the 10 ohm resistor.
5 mk
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5.9 marks
SECTION B (45 MARKS)
Answer ALL the questions in this section. All working for each question attempted must be
shown clearly.
(a)
Explain how radioactivity differs from any type of chemical reaction.
3 mk
(b)
Write in summary form, two properties of each of α, β and γ radiations.
6 mk
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6.9 marks
SECTION B (45 MARKS)
Answer ALL the questions in this section. All working for each question attempted must be
shown clearly.
(a)
What is meant by the terms
Electrochemical Equivalent, Voltameter, Cathode and Anode as applied in electrolysis?
4 mk
(b)
How long will it take to deposit 99 mg of copper in a copper voltameter which carries a
current of 3.0A. On which electrode is the deposition of copper taking place?
5 mk
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Section C
7.10 marks
SECTION C
Answer any FOUR questions from this section.
(a)
Identify any two different forms of energy and name the device which can convert each
form of energy to the other
4 mk
(b)
Pangani falls are 45 metres high. Determine the potential energy of 20 litres of water at
the top relative to the bottom. What is the Kinetic Energy of water molecules just before
reaching the bottom and explain what happens to the energy after the water reaches the
bottom?
6 mk
