Physics Paper 1 Questions - Mumias West Pre Mock Exams 2023

Instructions to the candidates;

• This paper consists of TWO sections: Sections A and B
• Answer ALL the questions in sections A and B
• ALL working MUST be clearly shown
• KNEC Mathematical tables and Non-programmable electronic calculators may be used
• Candidates should check the questions paper to ascertain that all the pages are printed as indicated and that no questions are missing

Take; g= 10N/kg

For Examiner’s Use

QUESTIONS

SECTION A (25 MARKS)

1. State two precautions to be observed when using a micrometer screw gauge (2marks)
2. The formula for determining weight of an object is given by w=mg Give the physical quantity represented by the letter g and state its SI unit (2marks)
3. Figure 1 shows water in a tank
   
   Determine the pressure exerted on the ground due the weight of the water (3marks)
   (take density of water to be 1000 kgm^-3)
4. A part from size of molecule, State two other factor that affect the rate of diffusion of a gas (2marks)
5. Figure 2 shows electric cables for power transmission
   
   Explain why they are not fixed tightly (2marks)
6. A half filled thermos flask is less likely to keep a liquid hot for a longer time than one which is completely filled Explain (2marks)
7.                
   1. Define the moment of a force and state the SI unit (2marks)
   2. A uniform metre rule is balanced at the 30 cm mark when a load of 08N is hung at the zero mark as shown in figure 3 below
      
      Determine the weight of the metre rule (2marks)
8. Figure 4 shows ice in a beaker
   
   Fig4
   State and explain the effect of raising temperature on the overal stability of the beaker and its contents (2marks)
9. The pointer of an unloaded spring reads 20 cm when a mass of 120g is applied to the spring, the pointer reads 28cm a pan in which a mass of 200g is placed is now hang from the spring and the pointer reads 35cm Determine the mass of the pan (3marks)
10. Sketch a displacement-time graph for a body thrown upwards and falls back to the ground (2marks)
11. State one property of a fluid that obeys Bernoulli’s effect (1mark)

SECTION B (55 MARKS)

12.                    
    1. Show that, for an inclined plane, its velocity ratio is given by, ¹/_sin θ where θ is the angle of inclination (3marks)
    2. Sketch a block and tuckle system of pullies with a velocity ratio of 4 (3marks)
    3. Figure 5 shows a cross-section of a handle of a screw jack 70 cm long and pitch of the screw is 08 cm
       
       Fig 5
       Given that the efficiency is 60%, determine:
       1. The velocity ratio of the system (2marks)
       2. If an effort of 50N is applied calculate the load that can be lifted (3marks)
13.                        
    1. Define specific heat capacity and state its SI unit (2marks)
    2. Equal masses of water and paraffin are heated for same length of time The final temperature of paraffin was found to be greater than the final temperature of water Explain the observation ( 2marks)
    3. A hot-water tank for a house contains 150kg of water at 15ºC the tank itself has a heat capacity of 6000 JK^-1 An immersion heater is used to heat the water to 50ºc the tank is well insulated and the power of the heater is 2500W (specific heat capacity of water =4200 JKg^-1K^-1)
       1. Find the amount of heat transferred to the water (2marks)
       2. Find how much heat is absorbed by the tank (2marks)
       3. Determine the time it will take the heater to raise temperature to 50ºC (3marks)
14.                  
    1. Explain the meaning of an ideal gas (1mark)
    2. Sketch a graph of volume against the inverse of pressure at a constant temperature (2marks)
    3. On the same axis of the sketch in 14 b) above, sketch the graph when temperature is raised for the same gas (1mark)
    4. A bubble of air of volume 1cm³ is released by a deep-sea diver at a depth where the pressure is 30 atmospheres Assuming its temperature remains constant Determine its volume just before it reaches the surface where the pressure is 15 atmosphere? (3marks)
    5. Figure 6 shows apparatus used in investigating a gas law Study it and answer the questions that follow
       
       
       1. State the law under investigation (1mark)
       2. Describe how the set up can be used to verify the law stated in (i) above (4marks)
15.                  
    1. Define the radian as applied in circular motion (1marks)
    2. A body in circular motion with constant speed is said to be accelerating Explain this observation (1mark)
    3. Figure below shows masses A, B and C placed at different points on a rotating table The angular velocity of the table can be varied
       
       
       1. State two factors that determine whether a particular mass slides off the table or not (2marks)
       2. State the mass that slides off last Give a reason for your answer (2mark)
       3. A ball of mass 100g tied to a light to a light string is being whirled in a vertical circle of radius 05m with uniform speed At the lowest position the tension in the string is 28N Calculate
          1. The angular velocity of the ball (3marks)
          2. The tension in the string when the ball is at the upper most position of the circular path (2marks) 
16.                          
    1. State two factors affecting the upthrust experienced by an object immersed in a fluid (2marks)
    2. Explain how a submarine is made to float and sink in water (2mark)
    3. Figure 8 shows a simple hydrometer
       
       
       1. Explain why the bulb is made wide (2mark)
       2. State the purpose of the lead shots in the glass bulb (1mark)
       3. Describe how the hydrometer can be made more sensitive (1mark)
       4. Describe how the hydrometer is calibrated to measure relative density (2marks)