Physics Paper 3 Questions - Maseno Mock Examinations 2022

QUESTIONS

QUESTION ONE.
PART A.
You are provided with the following:

• A rectangular glass block.
• 4 optical pins.
• A soft board.
• A plain paper.

Proceed as follows:

1. Place the glass block on the plain paper with one of the largest face upper most. Trace round the glass block using a pencil as shown in Figure 1 below.
   
2. Remove the glass block and draw a normal at B. Draw an incident ray AB of angle of incidence, i = 30º
3. Replace the glass block and trace the ray ABCD using the optical pins.
4. Remove the glass block and draw the path of the ray ABCD using a pencil. Measure length L and record it in table 1 below.
5. Repeat the procedure above for the angles of incidence given and complete the table. (7marks)
   Table. 1
   

   Angle iº	L(cm)	L2(cm2)	1/L2(cm-2)	Sin2i	1/L2   sin2i
   30
   40
   50
   60

6. Determine the average of  ¹/_L2    (2marks)
                                            sin2i 
7. Hand in your constructions on the plain paper together with the answer script. (1mark)
   PART B.
   You are provided with the following apparatus:
   
   • Two retort stands
   • Two bosses
   • A meter rule
   • A pendulum bob
   • A piece of cotton thread
   • A stop watch or stop clock
     Proceed as follows;
8. Tie the thread provided to the pendulum bob securely so that it is at the center of the thread (put the thread through the whole or loop of the bob up to the Centre and then make a knot).
9. Use your pen to mark on the loose ends of the thread, points A and B 50cm from the point where the bob is tied.
10. Fix the bosses on the stands at points 60cm above the bench. Suspend the bob between the two stands by tying the loose ends of the thread to the bosses at the points marked in (h) above. See figure 2 (A and B are the marked points).
    
11. Adjust the position of one of the stands (by moving it closer to the other), so that the distance d is 50cm. Give the bob a small displacement perpendicular to the plane containing the two portions of the thread and then release it. Measure the time for 10 oscillations. Repeat the measurement and record in the table 2 below.
12. Repeat the procedure in (k) for other values of d shown in the table and complete the table. (7marks)
    Table 2.
    

    Distance d(cm)	50	55	60	65
    Time to for 10 oscillations (s)
    Periodic time T (s)
    T2(s2)
    d/T2

13. Determine the average of ^d/_T2 (3marks)

QUESTION TWO
You are provided with the following apparatus:

• 2 size D dry cells.
• 100cm nichrome wire on a mm scale.
• A bulb (2.5v) and a bulb holder.
• 8 connecting wires (at least 4 with crocodile clips).
• Cell holder.
• A switch.
• A voltmeter (0 – 3V).
• An ammeter (0 – 1A).
• A jockey.

Proceed as follows;

1. Connect the apparatus provided as show in Figure 3. below.
   
2. Place the jockey at L = 20cm from P, then close the switch.
   Record the ammeter reading and the voltmeter reading in Table 3. below.
3. Repeat the experiment by placing the jockey at L= 40, 60, 70 and 80cm from P.
   Record your readings and complete the table. (9marks)
   Table 3.
   

   Length L(cm)	1(A)	Pd V(v)	1(mA)	Pd V(mV)	Log 1(mA)	Log V (mV)
   20
   30
   40
   50
   60
   80

4. Plot a graph of log I (mA) (y-axis) against log V(mV) (5 marks)
5. Determine the slope of the graph. (3marks)
6. Given that Log I = n log v + log k where k and n are constants of the lamp. Determine using your graph the value of k and n. (3marks)