Physics Paper 2 Questions and Answers - Mincks Group of Schools Mock Examinations 2022

INSTRUCTIONS TO CANDIDATES:-

• Write your Name, Index number, Admission number and school in the spaces provided above.
• This paper consists of two sections; A and B
• Answer all the questions in section A and B in the spaces provided
• All working must be clearly shown.
• Mathematical tables and electronic calculators may be used.
• This paper consist of 19 printed pages. You are advised to ascertain that all pages are printed as indicated.
• Take the earth’s gravitational field strength g = 10 m/s².

For Examiner’s Use Only:

QUESTIONS

SECTION A (25 MARKS)
Answer all questions in this section in the spaces provided.

1. The diagram below shows two parallel mirrors M1 and M2 and a ray of light being incident on one of the mirrors as shown.
   
   Trace the ray of light through the mirrors and indicate the angle of incidence on M1 (2 mks)
2. Two pins are hanging from a magnet as shown in the diagram below.
   
   Explain why the pins spread as shown in the diagram. (2mks)
3. An image I is formed infront of a concave mirror and on the principal axis as shown in the figure below.
   
4. The figure below shows a set up by a student.
   
   State and explain what happens to the sound from the buzzer as the bottle and its contents are cooled to 0°C. (2 mks)
5. Arrange the following waves in order of decreasing wavelength. (1mk)
   Infrared, X-rays, Microwaves, Radio waves, Red light.
6. Figure below shows an incomplete circuit of an electromagnet.
   
   Complete the circuit by drawing the windings on the two arms of the core such that A and B are both North poles when the switch is closed. (1mk)
7. Figure represents a step in charging a material B negatively by induction.
   
   
   1. What is the charge on Y? (1mk)
   2. Explain what happens at A. (1mk)
8. The graph below shows the variation of p.d. (V) across the terminals of a cell and current drawn from the cell.
   
   
   1. Use the graph to determine the electromotive force (emf) of the cell. (1mk)
   2. Draw a circuit diagram that may be used to obtain the values plotted in the graph. (2mk)
9. A vibrator is sending out eight ripples per second across a water tank. The ripples are observed to be 4cm apart. Calculate the velocity of the ripples. (3mks)
10. The figure below shows part of electric cooker coil.
    
    
    1. Why is the material labeled Y coiled? (1mk)
    2. State the property of material Y that makes it suitable for its use. (1mk)
11. An immersion heater rated 1500W is used continuously for 30 minutes per hour per day. Calculate the cost of electricity per week if the rate is Ksh. 6.70 per unit. (2mks)
12. Fig below shows a conductor y placed in a magnetic field. The conductor carries a current flowing into the paper.
    
    
    1. Sketch the resultant magnetic field between the poles of the bar-magnet. (1mk)
    2. Show on the diagram the direction of the force, F acting on the conductor (1mk)

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

13.                                  
    1. Figure below shows the path of light through a transparent material placed in air.
       
       
       1. Give a reason why the above ray is not refracted at the interface of air and the transparent material as shown in the diagram. (1mk)
       2. Calculate the refractive index of the transparent material. (3mks)
    2. An image is formed 10cm in front of a concave lens of focal length 15cm. calculate the position of the object in respect to the lens. (3mks)
    3. You are provided with the following apparatus to determine the focal length of a lens.
       • A lit candle.
       • A white screen.
       • A metre rule.
         With a aid of a labelled diagram, describe the procedure you would follow to determine the focal length of the lens. (3mks)
14.                    
    1. The figure below shows metal plates X and Y each fixed to an insulated stand. X is charged and Y is earthed. X is connected to an uncharged electroscope with a conductor.
       
       If plate Y is moved away from plate X,
       1. State what happens to the amount of charge on the plates. (1mk)
       2. State and explain the observation made. (3mks)
    2. The figure below shows an arrangement of capacitors connected to a 12V dc supply.
       
       Determine:
       1. The total capacitance of the arrangement. (2mks)
       2. The voltage across the 3μF capacitor. (3mks)
15.                        
    1. The figure below shows an attempt to supply each of the three lamps L1, L2 and L3 with a switch.
       
       
       1. Give a reason why this is a poor connection. (1mk)
       2. Redraw the diagram to show the correct positioning of the switches. (1mk)
    2. A wire placed between the pole of two permanent magnets is connected to a galvanometer as shown below.
       
       
       1. State what is observed when the wire is moved up and down. (2mks)
       2. Suggest two ways of increasing the magnitude of the effect you have stated in (i) above. (2mks)
       3. The figure below shows a simple transformer. Study it and answer the questions that follow.
          
          State and explain which coils are thicker. (2mks)
16.                    
    1. The figure below shows Zinc plate placed on the cap of a negatively charged electroscope.
       
       Ultraviolet radiation is made to fall on the plate as shown on the diagram.
       1. What happens to the leaf of the electroscope? (1mk)
       2. What would happen if radiation was red light? (1mk)
    2. In an experiment to find the relationship between frequency of a radiation and kinetic energy of the photoelectrons in a photoelectric device, the following graph was obtained.
       
       Use the graph to determine the Planck’s constant h. (3mks)
    3. Figure below shows the features of an X-ray tube.
       
       
       1. Explain the function of part labelled P. (1mk)
       2. Explain why the part labelled C gets very hot during production of X-rays. (2mks)
       3. Explain what is done to produce X-rays of shorter wavelength using the above X-ray tube. (1mk)
17.                    
    1. The figure below shows monochromatic source of light L behind a barrier with a single slit S placed behind another barrier with two identical slits S1 and S2. A screen PQ is placed in position as shown.
       
       
       1. What is the significance of S1 and S2? (1 mk)
       2. Explain what is observed on screen PQ. (2 mks)
    2. Waves pass from deep water to shallow water and refraction occurs.
       
       Calculate the speed of the waves in the shallow water. (2 mks)
    3. The figure below shows an a.c. signal on the screen of a Cathode Ray Oscilloscope.
       
       Determine the frequency of the signal given that the time base is set at 10ms/division. (2mks)
    4. Diagram (a) below shows the position of the bright spot on the screen of a C.R.O. when there is no signal on both Y and X plates.
       
       Indicate on the diagram (b) below what is observed on the display screen when the Y-plate is connected to a.c. signal and for (c) when X-plate is connected to a d.c. signal. (2mks)
       b).
       c).
18.                            
    1. The following reaction is part of a radioactive series.
       
       
       1. Identify the radiation r. (1mk)
       2. Determine the value of c. (1mk)
    2. At a certain instant the corrected count-rate registered on a detector placed close to an α-particle emitter is 200 per second and this falls to 50 per second in 12 minutes. Determine the half life of the source. (3mks)
    3. Study the rectification circuit below and use it to answer questions that follow.
       
       
       1. Briefly explain how the circuit works to rectify the alternating current. (3mks)
       2. Show on the diagram how a capacitor should be connected to smooth the output voltage. (1mk)
       3. In the grid provided, sketch a curve of smoothed output voltage against time. (1mk)
          

MARKING SCHEME​

	SECTION A (25 marks)
1.		1 1	CORRECT RAYS Correct angles
2	The ends of the pin acquire the same polarity thus they repel each other.	1 1
3.		2	Correct rays @ 1mk Position and nature of image (real, upright,magnified)
4.	The sound becomes faint/ magnitude of sound reduces On cooling the partial vacuum is created which minimizes the transmission of sound which requires a medium.	1 1
5.	Radio waves , Microwaves, Infrared, X-rays,Red light.	1
6.		1	Tied Both must be correct.
7.	Positive Electrons flow to the sphere from the ground	1 1
8.	1.52V	1 1 1	Must extrapolate. If not deny. Correct symbols Correct arrangement (both marks tied)
9.	V =fλ = 8 x 0.04 =0.32m/s	1 1 1	Formula Substitution Answer
10.	To increase the length of the conductor hence increasing the resistance. High melting point	1 1
11.	cost = 1500 x 30 x 6.70            1000   60 = Ksh. 5.025	1 1	Evaluation Answer (check units)
12.		1 1	Correct magnetic field pattern Direction of the force
	SECTION B (55 marks)
13.	The angle of incidence is equal to the critical angle of the transparent medium. η =    1           sin C η =    1           sin 50 = 1.305 v= -10cm f = -15cm U = 30cm                       The lens is placed between the lit candle and the screen. Adjust the position of the lens until a sharp focused image is formed  on the screen. Record the object and image distance u and v. Use the les formula  to determine the focal length f 1/f = 1/u + 1/v	1 1 1 1 1 1 1 1 1 1	Formula Substitution Answer Formula Substitution Answer Diagram
		10
14.	Remains constant. The leaf divergence increases. There is increase in potential difference between the plates. Since there is decrease in capacitance (but the amount of charge remains constant and capacitance is given by C = Q/V)                          CT = 7 x 1          7 + 1 = 0.875μF or  8.75 x 10-7F Q= CV = 8.75 x 10-7 x 12 = 1.05 x 10-5 C V3μF = 12 - 1.05 x 10-5                      1 x 10-6 =12 – 10.5 = 1.5V	1 1 1 1 1 1 1 1 1
		09
15.	The bulbs cannot be operated independently.                               Galvanometer deflects momentarily in one direction when the conductor moves upwards. The galvanometer deflects momentarily in the opposite direction when the conductor moves downwards.                   Using stronger magnets Increasing rate of movement of the conductor/ moving conductor faster.                   Primary coil Since more current flows through the primary coils they need to be thicker to minimize resistance.	1 1 1 1 2 1 1
		08
16.	The divergence of the leaf decreases/reduces. No change on divergence of the leaf is observed. h/e = gradient =    1.6 - 0.2       (7 - 3) x 1014 = 3.5 x 10-15 h =3.5 x 10-15 x 1.6 x10 -19 h = 5.6 x 10 -34Js                     P steps up the voltage used to accelerate the beam of electrons towards the target. Electrons hitting part C possess high kinetic energy/moves at very high speed. Most of its kinetic energy (about 99.5%) is converted to heat energy. By increasing the accelerating voltage/potential difference between the cathode and anode.	1 1 1 1 1 1 1 1 1
		09
17.	To produce two coherent sources of light. Alternating bright and dark fringes are observed. Bright fringes represent regions of constructive interference where the waves arrive in phase whereas the dark fringes represents regions of destructive interference where waves arrive out of phase. f = v/λ V =fλ = 2/1 = 2Hz =2 x 0.4 =0.8m/s T = 4 x 10/1000 = 0.04s f = 1/T = 1/0.04 = 25Hz	1 1 1 1 1 1 1 1 1
		09
18.	Beta particles 210 – 4 = 206                   During the first half cycle, X is positive in respect to Q hence D1 is forward biased and D2 is reverse biased thus current flows through the load R using path XYRX. In the next half cycle when Q is positive in respect to X D2 is forward biased and D1 is reverse biased hence current flows through the load using the path QYRQ. In both cycles the current flows through the load resistor R in the same direction YR.	1 1 1 1 1 1 1 1 1	Must show working Look out for alternative method Capacitor across the load