THE PRESIDENT’S OFFICE

MINISTRY OF EDUCATION, REGIONAL ADMINISTRATION AND LOCAL GOVERNMENT

COMPETENCE BASED SECONDARY EXAMINATION SERIES

PHYSICS FOUR ANNUAL EXAMINATIONS

FORM FOUR-2022

Instruction 

1. This paper consists of section A, B and C with a total of eleven [11] marks
2. Answer all questions in section A and B and two [2] questions from section C
3. Mathematical table and non – programmable calculator may be used
4. Cellular phones are not allowed in the examination room
5. Write your Examination number on every page of your answer sheet provided
6. Where necessary the following constants may be used

• Acceleration due to gravity g = 10mls²
• Density  of water, p= 1000 kg /m³ or 1g/cm³

SECTION A [15 MARKS]

1. For each of the items [i] – [x] choose the correct among the given alternatives and write its letter beside the item number in the answer sheets provided.

[i]. Which one among of the following is a factor on which up thrust exerted on a body by fluid depends:

1.  Volume of the fluid   B. Mass of the fluid   C. Viscosity of the fluid D. Density of the fluid                             E. Temperature of the fluid

[ii]. A layer of colour less water is carefully floated in a cylinder  on top of blue copper sulphate solution after a time, the water becomes blue, because of? 

1. Liquid friction   B. Density changes   C. Diffusion

4. Viscosity    E. Pressure changes

[iii]. If the mass of copper over the volume of copper is 8.9g/cm³. Find the volume 89g of copper  

1. 10 ^-5 cm   C. 10^-5m³
2. 0.1 cm³  D. 100CM³   E. 10cm³

[iv]. Aluminum is used in making motor engines, pistons and cylinders due to 

1. Its low density and high conductivity
2. Low density and maximum pressure
3. High density and varying mass
4. Its high conductivity and high density
5. Its heavy weight and low conductivity

[v]. A group of stars that forms a pattern shape in the sky is called………………..

1. Tides     C. A constellation   
2. A galaxy    D. The universe   E. The milky way

[vi]A basic condition for diffraction of wave when it passes through an opening is that 

1. The wavelength of the incident wave must be greater than the size of opening
2. The amplitude of wave must be smaller than the size of opening
3. The wavelength of the most almost be the corresponding size of the opening
4. The wavelength of the wave must almost be equal to the size of the opening
5. The amplitude of the wave must be greater than the opening

[vii]. When light is totally internally reflected from the boundary of a certain transparent material and air the critical angle is found to be 50⁰ the speed of light in the material is 

1. 2.1 x 10⁸m/s   
2. 2.2 x 10⁸m/s  
3. 1.94 x 10⁸m/s

D.2.3 x 10⁸m/s   

E. 3.0 x 10⁸m/s

[viii] Why buildings are constructed with wide foundation?

1. Because of power
2. In order to reduce pressure exerted by the building on the ground
3. So as to build large house
4. To increase pressure of the ground so as to maintain holding the house.
5. To avoid earth quake

[ix]. The energy from the hot rocks within the earth is called.

1. Tidal energy
2. Water energy
3. Cool- burning energy
4. Biomass energy
5. Geothermal energy

[x]. A reference was a certain device to judge football game in 90 minutes at MKAPA arena, that device was:-

1. Football    C. Stop watch  
2. Tape measure    D. 90 Minutes   E. Line man

2. Match the functions or importance’s of the layers of the atmosphere in List A with their corresponding  features in List B by writing the letter of the correct response beside the items number in the a lower sheets provided

Section B [60 marks]

Answer all questions

3. [a]. By using well labeled diagram, explain in short why the stem of the hydrometer is made thin and weighted with mercury or lead shorts? [06 marks]

[b]. A ship is made of steel and it is expected that it should sink in water. However it does not sink. At the same time a coin once dropped in water it will sink. How can you solve this contradiction so as to help a form one student who is totally confused? [04 marks]

4. [a]. It has been found the efficiency of a pulley system is always less than 100%. Giving two reasons explain the secret behind. [04 marks]

[b]. A meter rule is pivoted at its mid-point. If two objects of weigh 1.0N and 2.0N are suspended at 30cm and 90cm respectively from one end, calculate the position 

5. [a]. State the laws of refraction of light

[b]. The diagram below shows a ray of light incident on a glass prism at an angle.

Complete the diagram to show as it emerges from the other side [05marks]

[c]. Sketch a ray diagram to show the formation of a solar ellipse [03marks]

6. [a]. Give one difference and one similarity between a fuse and a circuit – breaker  [04 marks]

[b]. A cell supplies a current of 0.6A through a 2Ω coil and a current of 0.2A through a                           

752Ω coil. Calculate the e.m.f and internal resistance of the cell [06marks]

7.  [a]. Explain on the basic of conservation of linear momentum, how a fish propels itself forward by swishing its tail back and forth [04 marks]

[b]. A block and tackle system of 5 pulley is used to raise of 490N steadily through a is then 1800 J. calculate the efficiency of the system and efforts applied  [06 marks]

8. [a]. [i].Define half – life

      [ii]. A particular radioactive has a half – life of 2 hours A sample gives a count of 2400 per second at 11:00. When will the count have dropped to approximately 300 per second in the same counting system?  [04marks]

[b].  [i]. With diagram explain the mode of action of fuse.[03marks ]

 [ii]. Mention two [2] types of diode [02 marks]

Section C [25 marks]

Answer two [2] question form this section

9. [a]. Explain why notes of the same pitch played an a violin and a flute sound different? [03marks].

[b]. Give one reason why the frequency of the fundamental may alter during the day? [03marks]

[c]. A pipe closed at one end had a length of 10cm. if the velocity of sound in the air of the pipe is 340m/s, calculate the frequency of the fundamental and that of the first overtone [06 ½ marks]

10. [a]. [i]. hat is electromagnetic induction [01marks]

      [ii]. Explain carefully how the transformer works [03 ½ marks]

[b]. Briefly explain why the core of a transformer is made of thin layers of metal insulated from one another. [02marks] 

[c]. A transformer with primary oil of 400 turns and secondary oil of 200 turns is connected to the 240 V wire mains. If the primary current is 3A and secondary current is 5A.

      [i]. Calculate the efficiency of the transformer. [04marks]

      [ii]. Give reason why would expect this efficiency to be less than 100% [01marks]

                  [iii]. What is the type of transformer? Why are you [01marks?] 

11. [a]. Draw a labeled diagram of a longitudinal section view of the cathode ray oscilloscope tube showing its main features

[b]. What are the differences between a conductor, semiconductor and insulator interms of their energy levels? [04 ½ marks]

[c]. Name four gases that contribute to global warming and give one source of each [04marks]