Physics Paper 3 Pre Mock Questions and Answers - Mokasa I Joint Examination July 2021

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Instructions

  • Write your name, admission number, class and signature in the spaces provided at the top of the page.
  • Answer all the questions in the spaces provided in this paper.
  • You are supposed to spend the first 15 minutes of the 2 ½ hours allowed for this paper reading the whole paper carefully before your start.
  • Marks will be given for clear record of observations actually made, for their suitability and accuracy, and the use made of them.
  • Candidates are advised to record their observations as soon as they are made.
  • Electronic calculators and mathematical tables may be used.

FOR EXAMINER’S USE ONLY

Question(s)

Maximum Score

Candidate’s Score

1

20 marks

 

2

20 marks

 

TOTAL

40 marks

 



QUESTIONS

  1. You are provided with the following apparatus.
    • Voltmeter
    • A resistance wire, W mounted on a mm scale
    • Two dry cells and cell holders
    • 6 connecting wires
    • A switch
    • A jockey
    • Micrometer screw gauge (to be shared)
      Proceed as follows:
      1. Connect your apparatus as shown in the figure below
        q1 jhgtuhgds
      2. Measure the diameter, d of the resistance wire using a micrometer screw gauge.
                    d ……………………………………………………………………………….mm    (1/2 mark)
                    d ………………………………………………………………………………m        (1/2 mark)
      3. Place the jockey at L = 10cm, close the switch S. Read and record in the table the voltmeter reading.
      4. Repeat the procedure in (c) for other values of L and complete the table (7 marks)

        Length, L. (cm)

        10.0

        20.0

        30.0

        40.0

        50.0

        60.0

        Voltmeter, V(V)

                   

        1/L(m-1)

                   

        1/V(V-1)

                   
      5. Plot a graph of 1/V((y-axis) against 1/L (5 marks)
        graph ikygauiyd
      6. Determine the slope, S of the graph  (3 marks)
      7. Given that the y-intercept = 1/E, find the value of E.  (2 marks)
      8. Given that slope S is given by S = πd2 / βE find the value of β  (2 marks)
  2. You are provided with the following apparatus:
    • 1 rectangular glass block
    • 4 optical pins
    • 4 thumb tucks
    • 1 soft board
    • 1 plain paper
      Proceed as follows:
      1. Fix the plane sheet of paper on a soft board using thumb tucks as shown in the figure below
        q2 jgvauybvda
      2. Place the glass block on the sheet of paper so that it rests on its broader face and trace the outline PQRS.
      3. Remove the glass block.
      4. Draw a perpendicular to PQ at 0 such that PO is about ¼PQ.
      5. Draw a line AO such that angle x = 150
      6. Replace the glass block.
      7. Stick two optical pins P1 and P2 on the line AO.
      8. While looking through the glass block from side, SR, stick pins P3 and P4 such that they appear to be in a straight line with the images of pins P1 and P2.
      9. Remove the glass block and pins.
      10. Draw a line through the holes made by pins P3 and P4 to meet SR at C.
      11. Join C to O.
      12. Measure and record angle, y.
      13. Repeat procedure (e) to (l) for x = 250, 300, 400, 500 and 600 and tabulate the data
      14.  Complete the table for values of sin (900 – x) and cos y.  (8 marks)

        X(0)

        150

        250

        300

        400

        500

        600

        Y(0)

                   

        Sin(90 – x)

                   

        Cos y

                   
      15.  Plot a graph of cos y (y-axis) against sin (900 – x).(5 marks)
        graph ikygauiyd
      16. Find the slope, S, of the graph.  (3 marks)
      17. Given that, t cos y = sin(900 – x), where t is a constant, use your graph to find the value of t. (2 marks)
      18. Identify the significance of constant, t  (1 mark)
        NB: Hand in the trace-out together with your question paper


MARKING SCHEME


    1. Connect your apparatus as shown in the figure below
      q1 jhgtuhgds
    2. Measure the diameter, d of the resistance wire using a micrometer screw gauge.
                  d ……………………0.3………………………………………………………….mm    (1/2 mark)
                  d ……………………0.0003…………………………………………………………m        (1/2 mark)
    3. Place the jockey at L = 10cm, close the switch S. Read and record in the table the voltmeter reading.
    4. Repeat the procedure in (c) for other values of L and complete the table (7 marks)

      Length, L. (cm)

      10.0

      20.0

      30.0

      40.0

      50.0

      60.0

      Voltmeter, V(V)

      0.80 1.25 1.55 1.75 1.90 2.00

      1/L(m-1)

      10 5 3.333 2.5 2 1.667

      1/V(V-1)

      1.25 0.8 0.6452 0.5714 0.5263 0.5
    5. Plot a graph of 1/V((y-axis) against 1/L (5 marks)
      • Axis  1mark
      • Scale  1 mark
      • Plotting  2 Marks
      • Line  1 Mark
    6. Determine the slope, S of the graph  (3 marks)
      = 0.09426m/v
    7. Given that the y-intercept = 1/E, find the value of E.  (2 marks)
      slope = 0.33/v
      E= 3.03v
    8. Given that slope S is given by S = πd2 / βE find the value of β  (2 marks)
      =1.0e-6
  1. You are provided with the following apparatus:
    1 rectangular glass block
    4 optical pins
    4 thumb tucks
    1 soft board
    1 plain paper
    Proceed as follows:
    1. Fix the plane sheet of paper on a soft board using thumb tucks as shown in the figure below
      q2 jgvauybvda
    2. Place the glass block on the sheet of paper so that it rests on its broader face and trace the outline PQRS.
    3. Remove the glass block.
    4. Draw a perpendicular to PQ at 0 such that PO is about ¼PQ.
    5. Draw a line AO such that angle x = 150
    6. Replace the glass block.
    7. Stick two optical pins P1 and P2 on the line AO.
    8. While looking through the glass block from side, SR, stick pins P3 and P4 such that they appear to be in a straight line with the images of pins P1 and P2.
    9. Remove the glass block and pins.
    10. Draw a line through the holes made by pins P3 and P4 to meet SR at C.
    11. Join C to O.
    12. Measure and record angle, y.
    13. Repeat procedure (e) to (l) for x = 250, 300, 400, 500 and 600 and tabulate the data
    14.  Complete the table for values of sin (900 – x) and cos y.  (8 marks)

      X(0)

      150

      250

      300

      400

      500

      600

      Y(0)

      51 52.5 54.5 61 64 69

      Sin(90 – x)

      0.9659 0.9063 0.866 0.766 0.6428 0.5

      Cos y

      0.6293 0.6088 0.5807 0.4848 0.4384 0.3584
    15.  Plot a graph of cos y (y-axis) against sin (900 – x).(5 marks)
      • Axis  1mark
      • Scale 1 mark
      • Plotting 2 Marks
      • Line  1 Mark
    16. Find the slope, S, of the graph.  (3 marks)
      =0.6666
    17. Given that, t cos y = sin(900 – x), where t is a constant, use your graph to find the value of t. (2 marks)
      =1.5
    18. Identify the significance of constant, t  (1 mark)
      = Refractive index if the glass block
      NB: Hand in the trace-out together with your question paper 
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