THE UNITED REPUBLIC OF TANZANIA
NATIONAL EXAMINATIONS COUNCIL OF TANZANIA
CERTIFICATE OF SECONDARY EDUCATION EXAMINATION
2025
031/1 PHYSICS 1
(For Both School and Private Candidates)
NATIONAL EXAMINATIONS COUNCIL OF TANZANIA
CERTIFICATE OF SECONDARY EDUCATION EXAMINATION
2025
031/1 PHYSICS 1
(For Both School and Private Candidates)
Instructions:
1. This paper consists of sections A, B and C with a total of eleven (11) questions.
2. Answer all questions in sections A and B and two (2) questions from section C.
3. Section A carries sixteen (16) marks, section B fifty four (54) marks and section C thirty (30) marks.
4. Where necessary the following constants may be used:
(i) Acceleration due to gravity, \(g = 9.8 \text{ N/kg}\).
(ii) Density of water, \(\rho = 1000 \text{ kg m}^{-3}\).
(iii) Pie, \(\pi = 3.14\).
(iv) Specific heat capacity of water \(= 4200 \text{ J/kg}^{\circ}\text{C}\).
5. Time Allowed: 3 Hours
1. This paper consists of sections A, B and C with a total of eleven (11) questions.
2. Answer all questions in sections A and B and two (2) questions from section C.
3. Section A carries sixteen (16) marks, section B fifty four (54) marks and section C thirty (30) marks.
4. Where necessary the following constants may be used:
(i) Acceleration due to gravity, \(g = 9.8 \text{ N/kg}\).
(ii) Density of water, \(\rho = 1000 \text{ kg m}^{-3}\).
(iii) Pie, \(\pi = 3.14\).
(iv) Specific heat capacity of water \(= 4200 \text{ J/kg}^{\circ}\text{C}\).
5. Time Allowed: 3 Hours
SECTION A (16 Marks)
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 in the answer booklet provided.
(i) Which of the following ways as applied in Physics can be used by one person to convey the message to another person who is in the nearby village in the form of writings?
(ii) Carefully study logical steps 1 to 8 and then answer the question that follows:
1. Formulating a testable hypothesis 2. Data interpretation 3. Performing an experiment 4. Problem identification
5. Drawing conclusion 6. Asking questions 7. Data presentation 8. Data collection and analysis
Which steps show the best logical sequence for scientific investigation?
1. Formulating a testable hypothesis 2. Data interpretation 3. Performing an experiment 4. Problem identification
5. Drawing conclusion 6. Asking questions 7. Data presentation 8. Data collection and analysis
Which steps show the best logical sequence for scientific investigation?
(iii) Which precaution should be taken to avoid false reading before using a micrometer screw gauge in measuring lengths?
(iv) Why a person cannot push a car from inside when it is stuck in the mud or sand?
(v) Which action will increase the density of a substance?
(vi) A drop of water spreads on the surface of a smooth tiles while an equal sized drop of honey refutes spreading. Why are these wonders taking place?
(vii) When a sharp pencil of 5 g is placed on your hand on its tip, it will exert pressure on the hand. Calculate the maximum pressure the pencil will exert to you if it has dimensions shown in Figure 1.
(viii) An object of 5 cm is placed 25 cm away from the concave mirror of radius of curvature 24 cm. Deduce the position and characteristics of the image formed.
(ix) Suppose an engine raises 200 kg of water steadily through a height of 60 m in 20 s. If the upward force used is equal to the weight of water raised, calculate the power in kW.
(x) Which one of the following alternatives will decrease the capacitance of the variable parallel capacitor in a radio receiver if the dielectric materials remain constant?
2.
Match the descriptions of temperature terms in List A with their corresponding terms in List B by writing the letter of the correct response beside the corresponding item number in the answer booklet provided.
| List A | List B |
|---|---|
| (i) The temperature of melting ice. | A. Upper fixed point |
| (ii) The temperature scale that is used in the SI systems of units. | B. Thermodynamic scale |
| (iii) A measure of the average kinetic energy of the particles in a substance. | C. Fundamental interval |
| (iv) The temperature of boiling water. | D. Thermoelectric thermometer |
| (v) A temperature scale based on absolute scale. | E. Absolute zero |
| (vi) The point in which all molecular motion stops at \(-273.15^{\circ}\text{C}\). | F. Lower fixed point |
| G. Temperature | |
| H. Kelvin scale | |
| I. Celsius scale |
SECTION B (54 Marks)
3.
(a) Identify the type of lens which fits a person with:
(i) Short-sighted defect (2 marks)
(ii) Long-sighted defect (2 marks)
(b) Why concave mirrors used as shaving mirrors? Explain with an aid of a well labelled diagram. (5 marks)
(i) Short-sighted defect (2 marks)
(ii) Long-sighted defect (2 marks)
(b) Why concave mirrors used as shaving mirrors? Explain with an aid of a well labelled diagram. (5 marks)
4.
(a) Draw a diagram of simple mercury barometer showing clearly:
(i) The Torricellian vacuum. (2 marks)
(ii) The atmospheric pressure and height of the mercury. (3 marks)
(b) Figure 2 show rulers balanced at their centers of gravity in Case I and II. Determine the difference in weight between A and B. (4 marks)
(i) The Torricellian vacuum. (2 marks)
(ii) The atmospheric pressure and height of the mercury. (3 marks)
(b) Figure 2 show rulers balanced at their centers of gravity in Case I and II. Determine the difference in weight between A and B. (4 marks)
5.
(a) (i) Why a person jumping from a high ground to the floor bends knees upon making contact? (2 marks)
(ii) State the law or principle that supports your answer in (a) (i). (2 marks)
(b) A wooden plank is used to raise a heavy load from point A to point B as shown in Figure 3. Use Figure 3 to show that velocity ratio \(= \frac{1}{\sin \theta}\). (5 marks)
(ii) State the law or principle that supports your answer in (a) (i). (2 marks)
(b) A wooden plank is used to raise a heavy load from point A to point B as shown in Figure 3. Use Figure 3 to show that velocity ratio \(= \frac{1}{\sin \theta}\). (5 marks)
6.
(a) (i) How can a bimetallic strip be made? Briefly explain. (2 marks)
(ii) By using a simple diagram, show how a bimetallic strip made of iron and brass is formed when heated with the same temperature. (3 marks)
(b) Suppose 105 g of water at \(75^{\circ}\text{C}\) is added to 215 g of cold water at \(15^{\circ}\text{C}\) and the mixture is well stirred, determine the final temperature of the mixture if the heat absorbed by the container is neglected. (4 marks)
(ii) By using a simple diagram, show how a bimetallic strip made of iron and brass is formed when heated with the same temperature. (3 marks)
(b) Suppose 105 g of water at \(75^{\circ}\text{C}\) is added to 215 g of cold water at \(15^{\circ}\text{C}\) and the mixture is well stirred, determine the final temperature of the mixture if the heat absorbed by the container is neglected. (4 marks)
7.
(a) Briefly explain the three factors that determine the quantity of heat generated by an electric current. (4.5 marks)
(b) In a certain experiment, the p.d across the terminals of the cell was 1.1 V when a current of 0.20 A was being drawn from the cell and the p.d across the terminals of the same cell was 1.30 V when the current drawn from the cell was 0.10 A. Calculate the:
(i) Internal resistance of the cell. (2.5 marks)
(ii) Electromotive force of the cell. (2 marks)
(b) In a certain experiment, the p.d across the terminals of the cell was 1.1 V when a current of 0.20 A was being drawn from the cell and the p.d across the terminals of the same cell was 1.30 V when the current drawn from the cell was 0.10 A. Calculate the:
(i) Internal resistance of the cell. (2.5 marks)
(ii) Electromotive force of the cell. (2 marks)
8.
(a) Why is Venus nicknamed as twin planet of the Earth? (4 marks)
(b) Briefly explain:
(i) Two negative effects of volcanic activity on the earth's surface. (2.5 marks)
(ii) Two positive effects of volcanic activity on the earth's surface. (2.5 marks)
(b) Briefly explain:
(i) Two negative effects of volcanic activity on the earth's surface. (2.5 marks)
(ii) Two positive effects of volcanic activity on the earth's surface. (2.5 marks)
SECTION C (30 Marks)
Answer two (2) questions from this section
9.
(a) The cloud chamber is used for detecting ionized nuclear radiation. Explain how you can use it to detect the alpha and beta particles. (3 marks)
(b) One of the meteor laboratory scientists recorded the information such that the mass of renewed sample X was 20 g and after 150 days was 0.652 g.
(i) How many half lives had elapsed for sample X to decay to 0.652 g? (3 marks)
(ii) Using information obtained in (b) (i), determine the half-life of sample X. (3 marks)
(b) One of the meteor laboratory scientists recorded the information such that the mass of renewed sample X was 20 g and after 150 days was 0.652 g.
(i) How many half lives had elapsed for sample X to decay to 0.652 g? (3 marks)
(ii) Using information obtained in (b) (i), determine the half-life of sample X. (3 marks)
10.
(a) Draw a well labelled diagram to show the components of a cathode ray tube. (6 marks)
(b) Briefly explain three applications of diffraction of waves. (6 marks)
(c) One scientist was investigating the impact of tension on the frequency of vibrating wire. The following data were recorded: Length of a stretched wire was 30 cm, tension of wire was 900 N and slotted masses of 3 g and 12 g. Use these data to show how the masses on the vibrating wire affects its frequency. (3 marks)
(b) Briefly explain three applications of diffraction of waves. (6 marks)
(c) One scientist was investigating the impact of tension on the frequency of vibrating wire. The following data were recorded: Length of a stretched wire was 30 cm, tension of wire was 900 N and slotted masses of 3 g and 12 g. Use these data to show how the masses on the vibrating wire affects its frequency. (3 marks)
11.
(a) Draw the PNP and NPN transistor circuit symbols and indicate their three layers of the transistors and the direction of conventional current. (5 marks)
(b) Draw a well labelled electric bell circuit and explain how it works. (6 marks)
(c) (i) Use the Fleming's left-hand rule to explain the direction of the force in a current carrying wire. (3 marks)
(ii) What makes the efficiency of a transformer to be less than 100%? Briefly explain. (2 marks)
(iii) With reference to Faraday's law of electromagnetic induction, determine two factors which affect the magnitude of the induced e.m.f of the conductor. (4 marks)
(b) Draw a well labelled electric bell circuit and explain how it works. (6 marks)
(c) (i) Use the Fleming's left-hand rule to explain the direction of the force in a current carrying wire. (3 marks)
(ii) What makes the efficiency of a transformer to be less than 100%? Briefly explain. (2 marks)
(iii) With reference to Faraday's law of electromagnetic induction, determine two factors which affect the magnitude of the induced e.m.f of the conductor. (4 marks)