FORM FOUR MIDTERM EXAMINATION APRIL 2023 PHYSICS TIME: 3:00 Hours April, 2023 INSTRUCTIONS: i. ii. iii. This paper consists of sections A, B and C with total of ten (10) questions. Answer all questions in section A, B and C. All working should be in blue or black ink except drawings which must be in pencil. iv. Where necessary, the following constant may be used: Acceleration due to gravity g= 10m/s2 S.T.P, 760mmHg, 273K Heat capacity of Aluminium C = 23.062J/K Pie π = 3.14 v. QUESTION NUMBER FOR EXAMINERS USE ONLY SCORE 1 2 3 4 5 6 7 8 9 10 11 Page 1 of 6 EXAMINERS INITIALS SECTION A (16 Marks) 1. For each of items (i)-(x) choose the correct answer from among the given alternatives and write its letter in the answer sheets provided. i. The multiple reflection of the sound produced when it travels in an enclosed room refers as: A. Sound waves C. Transverse waves B. Resonance D. Echo E. Reverberation ii. The phenomenon that causes the dispersion white light into spectrum prism: A. Refraction B. Deflation B. Reflection D. absorption E. Interference. iii. The death of deep seas creatures is when brought shallow water. This happens because of: A. Their pressure inside bodies is greater to the surrounded pressure of water. B. Their pressure made inside bodies is less than that surrounded pressure of water C. The density of dead body is equal to that of water. D. Volume of body displaced is equal to volume of water. E. Pressure of dead body is equal to that of atmospheric pressure. iv. Aluminum is used in making motor engines pistons and cylinders due to its: A. Low density and high thermal conductivity. B. Low density and low thermal conductivity. C. It's good conductor of heat than copper. D. Thermal expansivity is high. E. It's stronger enough to maintain high temperature. v. One of the assumptions made when demonstrating how to determine specific heat capacity of substance by the mixture method is that: A. No heat lost to the surrounding, heat absorption by apparatus. B. Heat lost to the surrounding, heat absorption by apparatus. C. No heat lost to the surrounding, heat absorption by apparatus. D. Heat lost to the surrounding, no heat absorption by the apparatus. E. Calorimeter is apparatus for demonstrating. vi. The phenomenon of melting under pressure and re-freezing when pressure reduced is called: A. Ebullition B. Triple point of water B. Regelation D. Depression C. Equilibrium vii. Sweeting uses the cooling effects caused by: A. Osmosis B. Diffusion B. Freezing D. Evaporation C. Saturated water Page 2 of 6 viii. ix. x. A lens camera of focal length 15cm is used to take a picture of a man of height 1.8M, if a man is standing 10M ahead of the camera, what is magnification of the image: A. 1.8 B. 1.5 C. 0.00152 D. 0.00142 E. 0.005 Mercury from Spheroid drops when split on a wooden bench because: A. Its velocity is very high. B. It has relative density. C. It has high cohesive force. D. It has low surface tension. E. It is subjected to high atmospheric pressure A device consists of a coil rotating in an external magnetic field to produce electricity refers as: A. Transformer B. Electric bell C. Spark coil D. Generator E. Galvanometer 2. Match the items of list A with the correct responses from List B so as to produce meaning full phrase LIST A LIST B (i) Loudness A. Sound of regular frequency (ii) Voiceless B. Sound of irregular frequency (iii) Tone C. Rise and fall of sound waves (iv) Pitch D. Intensity of the sound larger amplitude (v) Thimble E. More reflection of sound in a closed room (vi) Reverberation F. Degree of the highest and lowest tone G. Quality of sound produced by an instrument SECTION B (54 Marks) Answer all questions from this sections 3. (a) A micrometer screw gauge has a error. State the reading that is observed on the instrument when used to measure the diameter of the wire whose actual diameter is 0.38mm (b) Briefly explain any four (04) sources of errors in measurements Page 3 of 6 4. (a) Figure 1 shows a defective straw used to suck milk from the glass It was observed that upon sucking the straw, milk did not rise up the straw. Explain this observation and hence suggest suitable solution for the scenario. (b) A rectangular block measures 8cm by 5cm by 4cm and has a mass of1200g. Determine the greatest pressure the block can exert on the floor. 5. (a) Figure 2 shows a round bottomed flask containing a coloured liquid. The flask is fitted with the capillary tube It is observed that on holding the flask with bare hands the level of the liquid in the capillary tube initially drops slightly and then rises. Explain this observation. Page 4 of 6 (b) An Aluminium solid of mass 26g absorbs 600J of heat when heated. If the initial temperature of it is 300C. Find its final temperature 6. (a) Why does the sky appear blue during the day as observed from the Earth surface (b) Which colour will be seen on a white shirt with Green spots when is illuminates with:i. Red light ii. Blue light iii. White light 7. (a) At different time’s scientist have proposed various descriptions of an atom to match the experimental evidence available. Briefly describe Plum pudding model as proposed by J.J Thomson. (b) The element tin has a total of 25 isotopes with the lightest isotope being. Assuming that all 25 isotopes exist and the difference in mass number of two successive elements is one. Write down the symbol for heaviest isotope. 8. (a) Figure below shows the graph of Velocity(m/s) against time (sec) for a small steal ball falling in a viscous fluid i. ii. Describe the motion of the steel ball as represented by part OA Give reason why the velocity of AB is constant? (b) A form four student throws a stone of mass 200g vertically upwards from the ground with the velocity of 80m/s and it lands back after a certain seconds. Determine the total distance travelled by the stone. SECTION C (30 Marks) Page 5 of 6 Answer only two questions from this section 9. (a) State the Hooke’s law (b)You are provided with five 20g masses, a meter rule, spring with a pointer, a retort stand and a clamp. i. Sketch a labelled diagram of the set up that may be used in order to verify Hooke’s law using these apparatus ii. State two measurement that should be recorded in order to plot a suitable graph so as to verify the Hooke’s law iii. Describe how the measurement in (ii) above can be used to determine the spring constant iv. Sketch the nature of the graph for elastic limit is not exceeded. (c) A helical spring stretches by 0.6cm when supporting a weight of 8.7N. Determine the extension when the same spring supports the weight of 10.3N 10.(a) Diagram below shows a bottle top opener being used to open a bottle From the diagram indicate the direction of Load and Effort (b) State the two ways in which an inclined plane can be made to reduce the applied effort when pulling a load along the plane (c) A block and tackle pulleys system of five pulleys and 96.4% efficiency is used to raise a load of 400N. i. Draw the diagram to show how the system can be set up in order to lift a load hence indicate position of load and Effort. ii. State the velocity ratio of the setup iii. Calculate the force needed to raise a 400N load 11. (a) With three points explain how Jovian planets and Rocky terrestrial planets differ from each other (b) With three points elaborate the shortfalls of heliocentric theory on the solar system. (c) Describe four properties of the Earth Page 6 of 6