THE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATIONS COUNCIL OF TANZANIA ADVANCED CERTIFICATE OF SECONDARY EDUCATION EXAMINATIONS
131/1 PHYSICS 1
(For Both School and Private Candidates)
Time 3 Hours Year: 2012
1. This paper consists of sections A and B with a total of ten (10) questions.
2. Answer all questions in section A and two (2) questions from section B.
3. Section A carries seventy (70) marks and Section B carries thirty (30) marks.
4. Marks for each question or part thereof are indicated.
5. Mathematical tables and non-programmable calculators may be used.
6. Cellular phones and any unauthorized materials are not allowed in the examination room.
7. Write your Examination Number on every page of your answer booklet(s).
8. The following information may be useful:
Acceleration due to gravity, g = 9.8m/s2.
Stefan's constant, = 5.67 x 10-8 Wrn -2K4
Radius of the sun, Rs 7.04 x 108m . Speed of light, c 3.0 x 108m/s .
Wien's constant, 2.9 x 10-3 mK .
The value of the ratio 9.0 x 109mF
Permeability of free space, go = 4m x 107NAO
Electronic charge, e = 1.6 x 109c.
Mass of electron, Me = 9.1 x 10-31 Kg
Velocity of sound in air, v = 340m/s. Plank's constant, h = 6.63 x 1034Js .
Avogadro's number, NA = 6.02 x 1026atoms/Kmol.
Radius of the earth, Re = 6.4 x 103km .
Coefficient of thermal conductivity of Aluminium = 210Wm-1 K-1
Distance of the Earth from the sun, R = 1.5 x 1011m Pie, IT = 3.14
1.(a)(i) Briefly explain two types of errors that are likely to occur whenever an experimental measurement is made.
(ii) The length, L of a simple pendulum which is about 0.5m can be measured within Imm. What accuracy is required in the measurement of the periodic time, T of 100 oscillations if the errors in L and T are to produce equal percentage in the calculated value of acceleration due to gravity, g?
(c ) (i) What is meant by the statement that "an equation is homogeneous with respect to its units"?
(ii) The stress S, required to fracture a solid can be expressed as s = k where, k is a d dimensionless constant, E is the Young's modulus and d is the distance between the planes of atoms separated by the fracture. If the equation is dimensionally consistent, find the dimensions of the physical quantity, X and suggest the meaning of this quantity.
(b) A meteorite is traced by radar as it falls through the earth's atmosphere when its altitude is 3.0 x 104m . The screen shows that the meteorite is travelling with a velocity of 58.3m/s at an angle of 28.30below the horizontal. In the absence of air and at re-entrance to the earth's atmosphere;
(i) How much time elapses before the meteorite strikes the earth?
(ii) What is the magnitude and direction of the velocity of the meteorite just before the impact with the earth?
3. (a)(i)A sailboat cannot be propelled by air blown on its sails from a fan attached to the boat. This is because as the air leaves the fan it exerts a reaction on the fan (and the boat) equal to the force that the air from the fan will exert on the sails. Since action and reaction are equal and opposite, the two forces will cancel each other.
(ii) Action and reaction cannot produce a net force on an object because they are equal and act in opposite directions.
(c) A particle rests on a horizontal platform which is moving vertically in a simple harmonic motion with amplitude of 50mm. If above a certain frequency the particle ceases to remain in contact with the platform throughout the motion:
(i) Determine the lowest frequency at which this situation will occur.
(ii) At what position will the particle cease to remain in contact with the platform?
(ii) An aluminium saucepan in contact with a hot plate has a base of diameter 20.0cm and a thickness of 0. 5cm If the saucepan contains water boiling away at the rate of 0.15gs -1, estimate the temperature at the lower surface of the saucepan vessel.
(c) A roof which measures 20m x 50m is blackened. If the temperature of the sun's surface is 6000k, calculate the solar energy incident on the roof per minute, assuming that half of it is lost when passing through the earth's atmosphere.
(b) (i) List down four necessary conditions for a stationary wave to be formed.
(ii) An open pipe of length 15cm and a pipe of length 11.5cm closed at one end are both surrounding their first overtones. If their notes are of the same frequency, what will be the end correction of the two pipes? State assumption made in arriving at your answer.
(c) A transverse sinusoidal wave is generated at one end of a long horizontal string of lineal density of 1.8 x 10-3 kg/m and is kept under tension of 12.0N by a bar which moves up and down repeating regularly twice each second through a distance of 0.25m. Determine the: (i) Amplitude.
(c) A cell of e.m.f, E and internal resistance, r is used to drive a current, I through a load of resistance, R. Show that for maximum electric power to be transferred to the load, a load resistance, R must be equal to the internal resistance, r of a cell.
(b) (i) What are the factors that influence the velocities of P and S waves?
(ii) The P and S waves from an earthquake with a focus near the earth's surface travel through the earth at a nearly constant speed of 8km-1 and 6km-1 respectively. If there is no reflection and refraction of waves, how long is the delay between the arrivals of successive waves at a seismic monitoring station at 900in the latitude from the epicenter of the earthquake?