Physics Paper 2 Questions and Answers - Maranda Pre-Mock Examinations 2022

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QUESTIONS

  1. State the condition under which the P.d across the terminals of a cell is equal to its e.m.f. (1 mark)
  2. Figure 1 shows the pattern of water ripples in a dam.
    1
    What information about the depth of the dam at point X can you deduce from the pattern? Explain your answer. (2 marks)
  3. Kiss Fm is broadcasting at a frequency of 70MHz. What is the wavelength of the waves, if the speed of the waves is 3.0 x 108 m/s? (2 marks)
  4. Figure 2a,2b and 2c show the process of charging an electroscope by induction.
    2
    It is observed that the leaf rises in (a),collapses in (b) and then rises in (c).explain why the leaf collapses in (b) (3mks)
  5. Give one reason why soft iron is used as a core of the coil in an electric bell. (1 marks)
  6. What property of light is suggested by the formation of shadows? (1mk)
  7. A student holds a large concave mirror of focal length 1M, 80cm from her face. State two characteristics of her image in the mirror. (2mks)
  8. Convex mirrors are used in cars as driving mirrors because they have a wide field of view. Sketch a labeled diagram to show the wide field of view. (2mks)
  9. Arrange the following in order of increasing frequency. Visible light, infrared radiation, X-rays, U.V radiation, Radio waves. (1 mark)
  10. State the reason why radio waves signals are easier to receive than TV signals in a place surrounded by hills. (1 mark)
  11. Figure 4 shows three capacitors connected between two points A and B.
    3
    Determine the capacitance across AB. (3 marks)
  12. Two magnets A and B in figure 2 were brought from a point high above a table towards a steel pin.
    4
    State with a reason which magnet will attract the pin at a bigger height above the table. (2mks)
  13. Sound is classified as a longitudinal mechanical wave. Explain why sound is classified as;
    1. A longitudinal wave. (1 mark)
    2. A mechanical wave. (1 mark)
  14. Figure 4 below shows a conductor in a uniform magnetic field carrying current in the direction shown.
    5
    Indicate on the diagram the direction of motion of the conductor. (1mk)
  15. Name the property of light applied in transmitting light signal in optical fibres. (1mk)

SECTION B (55 MARKS)
Answer ALL the questions in this section in the spaces provided

  1.      
    1. Figure 6 shows a narrow beam of white light incident onto a glass prism
      6
      1. What is the name of the phenomenon represented in the diagram? (1mark)
      2. Name the colour at X and Y. Give a reason. (3mks)
      3. What is the purpose of the slit? (1mk)
    2. Figure 7 below shows a narrow beam of white light onto a glass prism. The speed of yellow light in the prism is 1.8 x 108m/s.
      7
      1. Determine the refractive index of the prism material (speed of light in vacuum C =3.0 x 108m/s). (3mks)
      2. Show on the same diagram, the critical angle, c, and hence determine its value. (3mks)
  2. In an experiment to observe interference patterns of light waves, a double slit is placed close to the source as shown in figure 8
    8
    1. State the function of the double slit. (1mk)
    2. Briefly describe what is observed on the screen. (3mks)
    3. State and explain what is observed on the screen when the slit separation S1- S2 is reduced. (2mks)
    4. State and explain what is observed on the screen when white light is used in place of the monochromatic light. (3mks)
  3. Figure 9 shows how a near object O is focused ina defective eye
    9
    1. What problem does the observer face when viewing an object at the near point? (1mk)
    2. Sketch on the same figure how a distant object is focused by the eye. (2mks)
    3. State the nature of the defect. (1mk)
    4. A pastor is known to have the defect stated in (b) (ii) above how will the pastor handle a bible as he reads it. (1mk)
    5. How would you advise the pastor as he goes about correcting the defect? (1mk)
  4.      
    1. State Farady's las of electromagnetic induction
    2. Figure shows a bar magnet being moved towards a solenoid.the solenoid is connected to a galvanometer.
      10
      1. Indicate on the diagram the direction of the induced current in the solenoid. (1mark)
      2. Identify the pole induced at D (1mark)
      3. Explain the answer in 16b.(ii) (2marks)
    3. Explain how laminating the core of a transformer increases its efficiency (2mks)
    4. A transformer has 1000 turns in its secondary coil and 10 turns on its primary coil. An alternating current of 2.5A flows in the primary circuit when it is connected to a 12V a.c. supply.
      1. State the type of transformer. (1mk)
      2. Calculate the power input to the transformer. (3mks)
      3. Calculate the e.m.f. across the secondary coil. (3mks)
    5. In transmitting power why is it necessary to step up before transmission. Explain. (2mks)
  5.      
    1. Distinguish between electromotive force (e.m.f) and potential difference, p.d of a cell. (2 marks)
    2. Lead acid accumulators and alkaline accumulators are all sources of electromotive force. State one advantage of
      1. Lead acid accumulator over alkaline accumulator. (1 mark)
      2. Alkaline accumulator over lead acid accumulator. (1 mark)
    3. Three resistors of resistances 2.0Ω, 4.0Ω and 6.0Ω are connected together in a circuit.
      Draw a circuit diagram to show the arrangement of the resistors which gives.
      1. Effective resistance of 3.0Ω. (2 mark)
      2. Minimum resistance. (1 mark)
    4. In the figure below the voltmeter reads 2.1V when the switch is open. When the switch is closed, the voltmeter reads 1.8V and the ammeter reads 0.1A.
      11
      Determine;
      1. The e.m.f of the cell. (1 mark)
      2. The internal resistance of the cell. (3 marks)
      3. The resistance of the lamp. (2 marks)


MARKING SCHEME

SECTION A (25 MARKS)
Answer ALL the question in this section in the spaces provided

  1. When there is no current flowing out of the cell. ✓
  2. The dam is deeper at X✓. This is because the ripples / waves are far apart at that point ✓
  3. V = fλ → λ = v/f = 3  x 108
                               70 x 106
    = 4.286m✓
  4. The electroscope is earthed✓ thus the electrons flow from the leaf to the earth. ✓ this reduces the force of repulsion✓ between the leaf and the plate to zero / electroscope is discharged hence the leaf falls.
  5. It is easily magnetized and demagnetised✓
  6. Light travels in a straight line / Rectilinear propagation of light. 
  7.    
    • Magnified.
    • Upright/erect
    • Virtual Any 2 x 1 = 2mks
  8.    
  9. Radio waves, Infrared radiation, Visible light, U.V radiations, X-rays. ✓
  10. radio waves have longer wavelength✓ so are easily diffracted around the hills
  11. 1.3μF + 0.7μF = 2μF ✓
    1/2.01/2.0 = 2/2 = 1μF✓
    = 1 x 10-6F✓
  12. A✓ – It has a stronger magnetic field than B. ✓
  13.      
    1. It is transmitted in series of alternating compressions and rare factions ✓
      its direction of propagation is parallel to the disturbance producing it ✓
      Any one
    2. It requires a material medium for its transmission
  14.      
    12
  15.    
    13
  16. Total internal reflection
  17.    
    1.    
      14    
      1. Dispersion of light.
      2. X – Red 
        Y – Violet
        Red has the lowest frequency/longest wavelength hence least deviated while violet has the highest frequency/shortest wavelength hence most deviated. 
      3. Act as point source of light.
    2.     
      1. = 3.0 x 108
           1.8 x 108
        = 1.6667
      2. C on the diagram. 
        η =    1     ⇒Sin C = 1/η =     1    
              Sin C                        1.6667
        Sin C = 0.5999
        C = 36.86°
  18.      
    1. The double slit allows for coherent source of light to occur (light of same frequency and wavelength)
    2. A series of dark and bright frings √1are observed decreasing in intensity from the centre outwards
      The bright fringes are due to constructive interference √1while dark fringes are a result of destructive interfered √
    3. When the slit separation is reduced the distance between peaks on the interference pattern increases; this is because of increase in resolution power.
    4. A central white fringe will be formed followed by the other fringes taking the seven colours of the rainbow.√ This is because each colour of the rainbow will be refracted √ differently because of the varying wavelength√
  19.    
    15    
    1. Blurred image √
    2.  
      1.      
        16
        Incoming rays should be parallel. ✓
        Refracted rays to R √
      2. Long-sightedness or hypermetropia √
    3.      
      1. At arm length √
      2. Use spectacles with convex lens √
  20.      
    1. the magnitude of the induced emf is directly proportional to the rate of change of the magnetic flux linkage. (N/B the word linkage must be seen)
      Or
      Whenever there is change of magnetic flux associated with a conductoer am emf is induced in the conductor whose magnitude is directly proportional to the rate of change of magnetic flux linkage
    2.    
      17  
      1.     
        18
      2. N
      3. From the lenzs law the induced current flows in the direction such that it opposes the change causing it.therefore as the north pole of the magnet approches end D becomes North Pole to repel the incoming North Pole.
    3. Lamination increases the resistance of the core/reduces eddy currents,this reduces heating effect thus efficiency increases.
    4.      
      1. Step – Up transformer.
      2. PP = IPVP 
        = 2.5 x 12
        = 30W
      3. Vs = Ns/Np x Vp
        = 1000/10 x 12
        = 1200V
      4. Minimizing energy losses./power losses:
        High voltages leads to small output current thus less resistance and low heating effect on the cables since
  21.      
    1. E.m.f is the voltage across the cell when no current is flowing out of the cell (in open circuit) ✓1
      P.d is the voltage across the cell when current is flowing out of the cell (in a closed circuit) ✓1
    2.      
      1. most reliable✓1
        Long lasting✓1
        Cost - effective✓1 (any one)
      2. large currents can be drawn from them. ✓1
        Can be kept in a discharged condition for a very long time before the cells are ruined. ✓1
        They require very little attention to maintain✓1
        They are lighter hence more portable. ✓1 (any one)
    3.      
      1.    
        19
      2.    
        20
    4.    
      1. 2.1V✓1
      2. r = internal resistance
        0.3V/0.1 = 0.1/0.1r
        r = 3Ω✓
      3. Terminal voltage = P.d = 1.8 = IR
        R = Resistance of the lamp
        1.8/0.1 = 0.1/0.1R✓
        = 18Ω✓

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