1. 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  Friday morning 19/10/2007

Instructions

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

2. Answer all questions in section A and B, and two (2) questions from section C.

3. Section A carries 20 marks, section B carries 60 marks and section C carries 20 marks.

4. Cellular phones are not allowed in the examination room.

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

6. Where necessary use the following constants: 

Acceleration due to gravity g = 9.8 m/s²

Pi =

SECTION A (20 Marks)

Answer all questions in this section.

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

(i) A stone is thrown horizontally from the top of a building at a speed of 12 m/s. How long does it take to fall 45 metres vertically? (Assume negligible air resistance).

1. 1.0 sec. 
2. 5.0 sec. 
3. 3.0 sec. 
4. 8.0 sec. 
5. 2.14 sec.

(ii) Which of the following statements is correct? 

1. Friction acts in the same direction as motion.
2. Air friction can cause a body to become hot.
3. Certain lubricants can reduce friction to zero.
4. For a given body the frictional force depends on the area in contact with the surface. 
5. Walking would be made easier if friction did not exist.

(iii) The dew point is defined as the

1. rate at which water vapour present in the atmosphere evaporates
2. amount of water on grass found in the morning
3. amount of water vapour required to saturate air
4. water vapour content of the atmosphere
5. temperature at which water vapour present in air is just sufficient to saturate it.

(iv) When a pipe is played a sound wave x is produced inside the pipe and a sound Y is heard outside the pipe, then

1. x is transverse and Y is longitudinal
2. x and Y are both transverse waves
3. x is progressive and Y is stationary
4. x is stationary and Y is a progressive wave
5. x is progressive and Y is longitudinal.

(v) When a lighted match is brought near the negatively charged electroscope, the leaf of the electroscope collapses because the

1. heat increases molecular vibrations which knock off the electrons from the cap
2. flame provides energy for the electrons to escape from the cap
3. match emits Y-rays
4. positive charges from the air ionized by the flame are attracted by the cap
5. match emits ?-particles.

(vi) In the circuit shown in figure 1 the battery and the ammeter have negligible internal resistance. What will be the ammeter reading?

Fig. 1

1. 2.5 A 
2. 0.4 A 
3. 0.5 A 
4. 1.6 A 
5. 2.0 A

(vii) A conductor becomes a magnet when 

1. it is wrapped with a coil of wire
2. a soft iron core is used
3. an electric current flows through it
4. its resistance is increased
5. It is passed through an electric field

(viii) A mixed beam of Y-particles, ?-particles and ?-rays enters a magnetic field at right angles to the direction of the beam. Which of the following best represent the correct paths taken by the radiations?

(ix) A semi conductor diode is used for 

1. producing a.c. from a d.c. power supply
2. rectification
3. controlling energy losses
4. amplification
5. supplying heat in some electrical devices.

(x) Saturn as a member of the solar system

1. is the largest planet with no known satellites
2. is the planet seen by naked eye satellites with a temperature ­200°C
3. is the planet only seen through telescope and is the furthest from the sun
4. has five moons and a ring system
5. is the second largest planet with known natural satellites and a ring system.