Section A
1.
2 marks
Define momentum and state the Principle of conservation of momentum.
(a)
Define momentum and state the Principle of conservation of momentum.
2 mk
(b)
A projectile of mass 400g moving at 600m/s hits a movable target of mass 20kg which is at rest. The projectile and the target move on together after the impact. Find
3 mk
((b)(i)
the combined velocity just after the impact.
0 mk
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2.
3 marks
Sketch a graph to show the variation of density with temperature for a given mass of water heated from -5°C to +5°C.
(a)
Sketch a graph to show the variation of density with temperature for a given mass of water heated from -5°C to +5°C.
3 mk
(b)
What is the biological significance of this variation?
2 mk
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3.
5 marks
Explain why a bubble of air increases in volume as it rises from the bottom of a pond to the surface. If the volume of the bubble as it reaches the surface is double that at the bottom of the pond, estimate the depth of the pond. (Assume that the water temperature is uniform, the pressure at the water surface is $10^5 N/m^2$ and the density of water is $1000kg/m^3$)
(a)
Explain why a bubble of air increases in volume as it rises from the bottom of a pond to the surface.
2 mk
(b)
If the volume of the bubble as it reaches the surface is double that at the bottom of the pond, estimate the depth of the pond.
3 mk
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4.
2 marks
If $\frac{1}{u} + \frac{1}{v} = \frac{1}{f}$ and $m = \frac{v}{u}$, show that $m = \frac{v}{f} - 1$. Where f = focal length of the lens, u = object distance from the lens, v = image distance from the lens, m = magnification.
(a)
If $\frac{1}{u} + \frac{1}{v} = \frac{1}{f}$ and $m = \frac{v}{u}$, show that $m = \frac{v}{f} - 1$.
2 mk
(b)
A converging lens of focal length 15cm produces a real image four times larger than the object. How far, from the lens, is the object?
0 mk
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5.
5 marks
Distinguish between a star and a planet. If the radius traced by the path of the planet is 8400 km, calculate the speed of the planet in km/day. (Assume the planet makes 1 revolution in 400 days, and $\pi$ = 22/7).
(a)
Distinguish between a star and a planet.
2 mk
(b)
If the radius traced by the path of the planet is 8400 km, calculate the speed of the planet in km/day.
3 mk
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6.
5 marks
Use the above diagram to calculate the current when
(a)
switch K is closed while K is open.
2 mk
(b)
Both switches K and K are closed.
2 mk
(c)
switch K is open while K is closed.
1 mk
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7.
5 marks
(a)
Define:
(i) Altimeter
(ii) Barograph
2 mk
(b)
With the aid of a diagram, explain briefly how a bicycle pump works.
3 mk
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8.
5 marks
(a)
Briefly explain why a bat can fly in the dark without hitting objects?
2 mk
(b)
A hunter shoots a rifle and 6 seconds later he hears a sound echoed from a cliff. How far away is the cliff? (Velocity of sound = $3 \times 10^8 m/s$).
3 mk
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10.
5 marks
(a)
What do you understand by the term Photoelectron?
2 mk
(b)
With the aid of a clearly labelled diagram, describe a simple demonstration of the photoelectric effect.
3 mk
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15.
5 marks
Two cells each having an e.m.f. of 2.5v and internal resistance of 2Ω are connected in (i) series (ii) parallel. Find the current, in each case, when the cells are connected to a 5Ω resistor.
(a)
State Ohm’s law
1 mk
(b)
Two cells each having an e.m.f. of 2.5v and internal resistance of 2Ω are connected in
(i) series
(ii) parallel
Find the current, in each case, when the cells are connected to a 5Ω resistor.
4 mk
(c)
If a cell supplies a current of 0.6A through a 2Ω coil and a current of 0.2A through a 7Ω coil, calculate the e.m.f. and internal resistance of the cell.
5 mk
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