Physics Paper 2 Questions and Answers - Sukellemo Joint Pre Mock Exams 2022

QUESTIONS

SECTION A (25 MARKS)

1. The diagram below shows the image formed by a convex mirror. Complete the diagram to show the position of the object. (2mks)
   
2. Explain why sound cannot be heard from far when one shouts in a forest. (1mk)
3. The chart below shows an arrangement of different parts of the electromagnetic spectrum.
   

   Radio

   A

   Visible

   Ultra-violet

   X-Rays

   Gamma rays

   Name the radiation represented by A. (1mk)
4. The figure below shows a magnet. Point A and B are in front of the magnet.
   On the axes provided, sketch a graph showing how the magnetic field strength changes from A to B. (2mks)
   
5.      
   1. Machines at a textile industry experiences electrostatic forces at certain points. Suggest a method that can be used to reduce these forces. (1mk)
   2. A sharp point of a pin is held over a positively charged electroscope. State and explain the observation made on the electroscope.
      (2mks)
6. The figure below shows two conducting wires A and B passing through a horizontal piece of cardboard.
   
   1. Sketch the resultant magnetic field patterns when the currents of high magnitude are flowing on both wires as shown. (1mk)
   2. What is the resulting effect of the field on the wires at the loose ends? (1mk)
   3. If the current in B were to be reversed, state how resulting would affect the wire conductors.(1mk)
7. The figure shows a wave traveling along a medium.
   
   Determine the speed of the wave if the source produces 480 vibrations per minute. (3mks)
8. State two things that determines the carrying capacity of an accumulator. (2mks)
9. Explain why when the pinhole of a pinhole camera is enlarged, a brighter but very blurred image is seen on the screen (2mks)
10. Calculate the operating current of a heating element rated 3kW, 240 Volts. (3mks)
11. State two factors affecting resistance of a resistor. (2mks)
12. Distinguish between an amplitude and wavelength of a wave. (1mk)

SECTION B

13.      
    1. A lens forms an image four times the size of the object on the screen. The distance between the object and the screen is 60cm when the image is sharply focused.
       
       1. State with a reason what type of lens was used. (2mks)
       2. Determine:
          
          1. The object distance. (2mks)
          2. The image distance. (2mks)
    2. The figure below shows the basic parts of a simple lens camera.
       
       1. Name the parts labeled A and B. (2mks)
       2. State the function of each of the parts A and B. (2mks)
14. The graph below shows the variation of p.d (V) across the terminals of a cell and the current drawn from the cell.
    
    1. Use the graph to determine:
       
       1. The electromotive force (e.m.f) E of the cell. (1mk)
       2. The internal resistance r, of the cell given that E = V + Ir. (3mks)
    2. Draw a circuit diagram that may be used to obtain the values plotted in the graph. (2mks)
    3. Describe briefly how the circuit you have drawn may be used to carry out the experiment to obtain the values in the graph. (2mks)
15.      
    1. State Snell’s law. (1mk)
    2. A coin is placed beneath a transparent block of thickness 10cm and refractive index 1.56. Calculate the vertical displacement of the coin. (3mks)
    3. The speed of green light in a prism is 1.94 x 10⁸ m/s.
       
       1. Determine the refractive index of the prism material.
          (Speed of light in air = 3.0 x 10⁸ m/s). (2mks)
       2. Determine the critical angle of the prism material. (2mks)
    4. State two advantages of using optical fibre in communication. (2mks)
    5. The refractive indices of water and glass are ³/₂ and ⁴/₃ respectively. Find the value θ in the figure below.(3mks)
       
16. The figure shows a system of capacitors connected to 100V supply.
    
    1. Determine:
       
       1. The effective capacitance of the circuit. (3mks)
       2. The charge through the 6µF capacitor. (3mks)
       3. The p.d. across the 8µF capacitor. (4mks)
    2. State two factors that affect the capacitance of a parallel plate capacitor. (2mks)
17. Some plane water waves were produced in a ripple tank. They pass from a region of deep water into a region of shallow water. The figure shows what the waves look like from above.
    
    1. State what happens at the boundary to:
       
       1. The frequency of the waves. (1mk)
       2. The speed of the waves (1mk)
       3. The wavelength of the waves (1mk)
    2. The waves have a speed of 0.12 m/s in the deep water. Wave crests are 0.08m apart in the deep water. Calculate the frequency of the source producing the waves. (2mks)
    3. State one difference between a stationary wave and a progressive wave. (1mk)
    4. The figure below represents crests of straight waves produced in a ripple tank.
       
       Determine the wavelength of the waves. (2mks)
    5. In an experiment to observe interference of light waves, a double slit is placed close to the source S of light as shown in the figure below.
       
       1. State the function of the double slit. (1mk)
       2. Describe what is observed on the screen. (2mks)
       3. State what is observed on the screen when the slit separation is reduced. (1mk)

MARKING SCHEME

1.      
   
2. Tree absorbs sound
3. Microwaves
4. 
   
   Graph shouldn't touch horizontal axis
5.      
   1. The metal part of the machine should be pared to neutralized any unbalanced changes developed
   2. The leaf collapses
      The electrons flows from the ground and discharges at the sharp point
6.    
   1.    
      
   2. Wires attract each other
   3. Wire would repel each other
7. Wavelength = 40cm = 0.4
   Frequency = 480 = 8hZ
                         60
   speed = fλ
   = 0.4 x 8 = 3.2m/s
8. The surface area of the plates
   Number of plates
9. The additional brightness of the resultant image is due to light which gets into the camera through the enlarged hole
   The image is blurred due to overlapping of different images falling on the same spot
10. Power: P = VI
    I = P/V = 3000
                    240
    = 12.5A
11. Length of conductor 
    Cross sectional area of the conductor
    Temperature
12. Amplitude is the maximum displacement of the particle of the medium by the wave while wavelength is the distance between two constuctive particles in phase or distance between two successful crests or troughs
13.      
    1.    
       1. Convex(converging) lens; image formed is rela
          Concave length does not form real images
       2.      
          1. m=v/u
             4 = v/.u
             u + v = 60cm
             5u/5 = ⁶⁰/₆
          2. V= 4u = 4 x 12 = 48cm
             or v = (60 - 12)cm = 48cm
    2.    
       1. A - Shutter
          B - Diaphragm
       2. A- Allows light to reach the film for a precised period of time when the camera is in operation
          B - Controls/regulates the amount of light entering the camera
14.      
    1.    
       1. emf = 1.4 + 6/10 x 0.2 volts
          = 1.52volts; graph line must be produced to cut the voltage axis 
       2. =(1.4 - 0.8)
            (0.2 -1.26) 
          = 0.6
          1.06
          r = 0.57
    2.      
       
    3. With the switch closed, adjust the rheostat so that current is at its minimum. Increase the current in stops using/adjusting the rheostat and for each current I note and record the corresponding value of p.d(v) across the cell
15.      
    1. The ratio of the sine of angle of incidence to the sin of the angle of retraction is constant
    2. P =   Real depth  
            Apparent depth
       1.56 = 10  
       1.56   1.56
       x = 6.410
       Vertical displacement = 10 - 6.410
       = 3.59cm
    3.    
       1. n = velocity of light in vacuum
                velocity of light in medium
          = 3.0 x 10⁸ 
            1.94 x 10⁸ 
          n = 1.046
       2.   1    = 1.546
          sinC
          Sin =   1   
                  1.546
          C = 40.30
    4. Minimal energy losses due to total internal reflection 
       Large quantity of data can be converted per second or unit time
       It's flexible
    5. 
       
       wⁿg = wⁿq
       aⁿg = ²/₃ x ⁴/₃ = ⁸/₉
       sin i = ⁸/₉
       sin r
       Sin r = sin i x 9
                       8
       = 0.5 x 9 = 0.056
              8
       r = 34.2
16.    
    1.      
       1. 4+8 = 12F
          ¹/_ct = ¹/₁₂ + ¹/₆ = ³/₁₂
          cT = ¹²/₃ = 4F
       2. Q = C₁V
          = 4 x 100
          = 400μC or 4 x 10^-4C
       3. P.d across 6F capacitor, V1 = Q/C = ⁴⁰⁰/₆ = 66.67V
          P.d across 8F capacitor = 100 - 66.67 = 33.33r
    2. Area of overlap
       Distance between plates
       Type of dielectric between the plates
17.    
    1.    
       1. Frequency not affected
       2. Speed reduces
       3. Wavelength reduces
    2. f = v/ λ
       0.12 = 1.5Hz
       0.08
    3. Stationary wave
       • No energy is transferred from source
       • Wave form does not appear to move
         Progressive wave
       • Energy is transferred from source
       • Wave form moves away continuously
    4. 9/6
       = 1.5cm
    5.    
       1. The slits S1 and S2 act as current sources of light each difracting the light wave that is incident
       2. Alternating bright and dark fringes are observed
          Bright fringes are observed at point of constructive inference and dark fringes at points of destructive interference
       3. The distance between the bright fringes increases