THE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATIONS COUNCIL

CERTIFICATE OF SECONDARY EDUCATION EXAMINATION

031/1 PHYSICS 1

(For Both School and Private Candidates)

Time: 3 Hours Monday, 15^th October 2012 a.m.

Instructions

1.This paper consists of sections A, B and C.

2.Answer all questions in sections A and B and one (1) question from section C.

3.Calculators and cellular phones are not allowed in the examination room.

4.Write your Examination Number on every page of your answer booklet(s).

5.Where necessary the following constants may be used:

(i)Acceleration due to gravity, g = 10 m/s² or 10 N/kg

(ii)Atmospheric pressure = 0.76 mHg

(iii)Density of water = 1 g/cm³

(iv)Pi, π = 3.14

SECTION A (30 Marks)

Answer all questions in this section.

1.For each of the items (i) – (x), choose the correct answer among the given alternatives and write its letter beside the item number.

(i)One advantage of the lead-acid accumulator is that

1. Its internal resistance is high
2. Its p.d. is less than 2 V
3. It can be recharged
4. Its e.m.f. is more than 10 V 
5. It supplies only a small current.

(ii)When an object moves around a horizontal circle of centre O with a constant speed its acceleration will be:

1. zero
2. towards the centre
3. away from the centre
4. along the tangent to the circle
5. along the direction of rotation

(iii)A total eclipse of the Sun is due to

1. the Moon coming between the Earth and the Sun
2. the Earth coming between the Moon and the Sun
3. the Moon reflecting light away from the Earth
4. the Sun coming between the Earth and the Moon 
5. the Earth reflecting light away from the Moon.

(iv)Short-sightedness in a human eye is due to

1. eyeball being too short 
2. eyeball being too large
3. eye lens being too weak
4. eye lens being smaller than retina
5. eyeball being larger than retina

(v)In Figure 1, a hydraulic press P is used to raise a load of 10000 N. A force F of 25 N is applied at the end of a lever pivoted at O to just raise the load.

Figure 1

What will be the value of force X applied to the press?

1. 1500 N
2. 100 N
3. 1125 N
4. 33.33 N
5. 13.33 N

(vi)The note from a plucked guitar will have a low pitch if the string is

1. thick and long
2. thick and slack
3. thin and slack
4. thin and short 
5. thick and short.

(vii)Lenz’s law can be applied to predict the

1. magnitude of back e.m.f. in a circuit
2. magnitude of induced current in a circuit
3. direction of applied e.m.f. across the circuit 
4. direction of induced e.m.f. in a circuit 
5. direction of the applied e.m.f. within a circuit.

(viii)The half-life of a certain radioactive element is 12 hours. What fraction of an element will have disintegrated in 72 hours?

1. 1/64
2. 1/16
3. 1/32
4. 1/8
5. 1/72

(ix)The mass of an atom depends on the number of

1. protons only
2. neutrons, electrons and protons
3. electrons and protons
4. neutrons and protons
5. electrons and neutrons

(x)The interior structure of the Earth is composed of three major zones which are:

1. magma, mantle and the core
2. lava, crust and magma
3. hypocenter, crust and the mantle 
4. the core, lava and hypocenter 
5. crust, mantle and the core.