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535/1 2¼ hours | UGANDA NATIONAL EXAMINATION BOARD Uganda Certificate of Education PHYSICS Paper 1 Time: 2¼ hours |
1990 PAPER 1
1. Which one of the following list contains vector quantities only?
A. Kinetic energy, potential energy, velocity
B. Acceleration, displacement, force
C. Displacement, kinetic energy, power
D. Time, velocity, density
2. Which one of the following cannot generate e.m.f?
A. magnetization B. chemical reaction
C. electromagnetic induction D. the piezo electrical effect
3. The process by which a substance emits particles spontaneously on its own is called
A. radiation B. radioactivity
C. photoelectricity D. thermionic emission
4. The magnitude of a force on a conductor carrying electric current in a magnetic field does not depend on the
A. length of the conductor B. magnitude of the current
C. magnetic field. D. direction of the current
5.
A ray of light traveling in air is incident as shown in the above figure. The ray is partially reflected and refracted. Calculate the angle of incidence
A. 3 00 B. 450 C. 500 D. 800
6. A charge of mass 9.1×10-31kg experiences a force of 9.1×10-28N in an electric field. What is the acceleration of the charge
A. 8.3×10-59ms-2 B. 1.0×10-3ms-2
C. 8.3×10-3ms-2 D. 1.0×103ms-2
7. The table below shows the numbers of the respective particles constituting atoms of elements P,Q,R and S
Element | Neutrons | Protons | Electrons |
P | 0 | 1 | 1 |
Q | 2 | 1 | 1 |
R | 2 | 2 | 2 |
S | 2 | 3 | 3 |
The isotopes are
A. P and Q B. Q and R C. Rand S D. Q and S
8. When a balloon filled with hydrogen is released into the air on a calm day, it
A. rises to definite height when the pressure inside and outside are equalized
B. rises until the pressure inside reduces to zero
C. rises for a while and then bursts
D. comes to the ground and darts around.
9. When a metal sphere is dropped in a viscous fluid, it eventually attains a steady velocity called
A. turbulence velocity B. terminal velocity
C. viscous velocity D. streamline velocity
10.
The above figure shows an inverted flak containing water whose temperature is just below boiling point. Cold water from a tap is allowed to flow on the flask. Which of the following is likely to happen? The
A. water vapour will condense to raise the pressure on the flask
B. water in the flask will expand and cause the cork to come off
C. water in the flask will boil for a while
D. temperature of the surrounding will drop drastically
11. The copper atom 6329Cu, has
Electrons protons Neutrons
A. 29 29 34
B. 34 34 29
C. 34 29 29
D. 34 29 34
12.
The minimum force required to raise a load of 100N is 25N using the block and tackle system in the figure above. Calculate the efficiency of this block and tackle system
A. 50% B. 75% C. 80% D . 100%
13.
The two magnets labeled M in the diagram in the above figure will
A. attract each other whatever the polarities of P and Q
B. attract each other if P and Q are of opposite polarities
C. attract each other if P and Q are north poles
D. repel each other whatever the polarities of P and Q
14. A uniform metre rule pivoted at the 25cm mark balances when a mass of 0.15kg is hung at the 8cm mark. Calculate the mass of the metre rule
A. 0.020kg B. 0.048kg C. 0.102kg D. 1.020kg
15. The brightness of the image formed by a pin hole camera depends on
A. the size of the object B. The shape of the object
C. the size of the pinhole D. the shape of the pinhole
16. The following are some of the uses of x-rays except
A. treatment of cancer B. preservation of food
C. detection of flaws in welded joints D. archeological dating
17. If a mercury barometer reads 760mm of mercury, what is the atmospheric pressure in Nm-2(the density of mercury is 1.36×104kgm-3)
A. 1.03×104Nm-2 B. 1.36×104Nm-2
C. 1.03×105Nm-2 D. 1.36×105Nm-2
18. **************
The above graph shows how the mass of a radioactive element, X, varies with time. How long will it take for the mass of X to reduce to 0.25g if the initial mass is2.0g?
A. 100years B. 150years C. 200years D. 300years
19. A galvanometer reads 0.05A at full scale deflection and has resistance of 2.0Ω. Calculate the resistance that should be connected in series with it to convert it to a voltmeter which reads 15V at full scale deflection
A. 10Ω B. 280Ω C. 298Ω D. 980Ω
20.
A vertical force of 4N and horizontal forces of 6N and 9N were applied on a block as shown in the diagram above. Calculate the magnitude of the resultant force on the block.
A. 3N B. 5N C. 15N D. 19N
21.
The diagram in the above figure shows a transverse wave. All the distances are in centimeters. Which of the following pairs of measurements are correct?
Wave-length(cm) amplitude (cm)
A. 2 2
B. 2 4
C. 4 2
D. 4 4
22. An electric kettle contains 2kg of water at 300C. When the is switched on, the temperature of the water rises to 500C in 3min. calculate the resistance of the kettle if the current flowing is 4A
A. 29.2Ω B. 58.3Ω C. 23.3Ω D. 3500Ω
23. The statement which best explains why most metals become softer when heated is that
A. the cohesive forces between the particles are weakened
B. the particles of the metals are weakened
C. the electrons around the nuclei of the particles move apart leaving the particles at fixed positions
D. the ionic forces between the particles are weakened
24.
The frequency of the electromagnetic wave represented in the figure
above is (velocity of light is 3.0×108ms-1)
A. 3x5x108/4x25Hz B. 3x100x108/25Hz
C. 25×100/3×108Hz D. 3x5x100x108/4x25Hz
25.
The diagram above illustrates an experiment to determine the refractive index of glass. Which one of the following graphs would give a straight line through the origin.
A. against B. sin i against r C. sin r against i D. i against r
26.
Two identical cells each of emf 2.0 V and negligible internal resistance are connected as shown in the figure above. Calculate the current through the 8Ω resistor when switch Sis closed
A. 0.25A B. 0.50A C. 2.00A D. 4.00A
27. A car starts form rest and accelerates uniformly at 2ms-2. Find the distance it covers in 6s
A. 12m B. 36m C. 72m D. 108m
28. A rectangular block of tin is 0.5 m long and 0.01m thick. Calculate the width if it has a mass of 0.365 kg and density of 7.3×103 kgm-3
A. 0.001m B. 0.010m C. 0.100m D. 1.000m
29. To produce a stationary wave, there must be two waves of the same
A. frequencies and speed but traveling in opposite directions
B. frequencies and amplitudes but traveling in opposite directions
C. frequencies amplitudes and speed and traveling in the same direction
D. frequencies, speed and amplitudes but traveling in opposite directions
30. The amount of heat required to raise the temperature of equal masses of metals X and Y through the same temperature is 3600J and 4800J respectively. Calculate the specific heat capacity of Y, given that the specific heat capacity of X is 300Jkg -1K-1
A. 12Jkg-1K-1 B. 16Jkg-1K-1
C. 225J kg-1K-1 D. 400Jkg-1K-1
31. In a four stroke internal combustion engine, the work required for initial induction and compression comes from
A. rotation KE stored in the flywheel B. movement of the steering wheel
C. separate starter motor D. sparking plug
32.
Calculate the current in the 2Ω resistor in the circuit in the above figure
A. 0.5A B. 0.8A C. 2.0A D. 2.8A
33. If a negatively charged ebonite rod is brought near the cap of a negatively charged electroscope, the leaves
A. decrease in divergence B. increase in divergence
C. remain unchanged D. gain positive charges
34. A liquid of density 1.03×103kgm-3 fills a vessel of uniform cross-sectional area of 10-3m2 to a depth of 0.24m. Calculate the force exerted by the liquid on the bottom of the vessel
A. 1.03×10-1N B. 2.472×10-1N C. 1.03N D. 2.472N
35. Which of the following diagrams shows the correct display of the wave form of an a.c voltage on the screen of a cathode ray oscilloscope?
36. A bullet of 150g is fired with a speed of 400ms-1. The rifle recoils with a speed of 10ms-1. Find the mass of rifle
A. 0.3kg B. 0.6kg C. 3.0kg D. 6.0kg
37. Calculate the cost of running four 40W lamps and three 60W lamps for 5hrs if electric energy costs sh.10 per kilowatt-hour unit.
A. sh. 3.4 B. sh 17 C. sh 34 D sh. 50
38. When a fish in water is viewed by an observer in air, it appears to be at a position different from where it actually is because of
A. reflection B. refraction C. interference D. dispersion
39. Very high voltages are used when distributing electrical power from the power station because
A. some electrical equipment require very high voltages
B. currents are lower, so energy loses are smaller
C. very high voltages are generated at the power stations
D. there is less likelihood of the transmission lines being struck by lightning
40. A person at a distance of 180m from a cliff produces a sound and hears the echo 1.5s later. Calculate the speed of sound in air
A. 120ms-1 B. 240ms-1 C. 270ms-1 D. 340ms-1
SECTION B
1. (a) The diagram in the figure below shows two identical bar magnets placed close to each other. On the diagram, draw the resultant magnetic field pattern
(b) Explain each of the following observations:
(i) A magnet not stored in soft iron keepers becomes weaker
(ii) heat destroys magnetism
2. An ammeter connected in series with a cell and a 2Ω resistor reads 0.5A. When the 2Ω resistor is replaced by a 5Ωresistor, the ammeter reading drops to 0.25A. Calculate
(i) The internal resistance of the cell
(ii) the emf of the cell
3. A dam at a height of 550m above sea level supplies water to a hydroelectric generating station which is at a height of 50m above sea level. 2000kg of water pass through the turbines in 1 second
(a) Calculate
(i) the potential energy per second
(ii) the maximum electrical power output of the station if the whole system is 80% efficient
(b) Find the velocity of the water when it reaches the generating station
4. (a) Define specific latent heat of vaporization
(b) ********
The above graph shows the variation of temperature with time for 10g of water heated from room temperature to boiling using a 200W heater
(i) At what temperature did the water boil (ii) calculate the specific latent heat of vaporization of water.
5. (a) State Hooke’s law.
(b)
The figure above shows a graph of extension against load for a copper wire.
(i) Name points B and C
(ii) Explain what happens to the wire between O and A (iii) What happens to the wire just after point C.
6. A torch bulb, lead plates dipped in dilute sulphuric acid and a battery of .e.m.f 12V are connected as shown in the figure below.
(a) (i) What would be observed if switch K1 is closed. Give a reason for your answer
(ii) State what is observed when K1 is opened and K2 is closed (iii) K2 was closed for sometime and then opened and K1was closed. State what was observed
(b) State the energy changes which take place in (a)(ii)
7. (a) Give one reason why transformer cores are
(i) Made of iron
(ii) laminated
(b) A transformer has 200 turns on the primary winding and 3000turns on the secondary. A voltage of 1600V is fed to the primary. Calculate the voltage output on the secondary.
8. Two identical masses each of 1kg are hung from strings 10m above the surface of the earth and the moon respectively.
(a) If the acceleration due to gravity on the moon is 1.6m-2, compare the tensions in the strings
(b) The string suspending the mass on the moon is cut so that the mass falls freely to the surface of the moon. Find the kinetic energy of the mass on reaching the surface of the moon.
9. The figure below shows the arrangement of a simple projector.
(a) Name the parts labeled A and B
(b) On the diagram, draw rays to show the final position of the image on the screen
(c) What is the role of B
10. *******
The displacement-time graph above shows how a boy moves with reference to his home. With reference to his home, find
(i) the position of the boy when he started moving
(ii) when the boy was at home
(iii) the average velocity of the body.
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