Physics P3 Questions and Answers with Confidential- Form 3 Term 3 Opener Exams 2022

INSTRUCTIONS TO CANDIDATES

1. Write your name and admission number in the spaces provided.
2. Answer all questions in the space provided.
3. All working must be clearly shown where necessary.
4. Non-programmable silent electronic calculation may be used.
5. Candidates should check the questions paper to ascertain that all pages are printed as indicated and that no question is missing.

QUESTIONS

Question 1
You are provided with the following apparatus

• Two complete retort stands.
• A metre rule
• Two pieces of thread (120cm and 20cm)
• A stop watch
• A piece of masking tape
• A pendulum bob
• A half metre rule

1.                        
   1.                
      • Attach one end of string to the metre rule at the 10cm mark by fastening a loop of string tightly round the metre rule.
      • Fix the string at this point with a piece of masking tape
      • Tie the string in the second loop at 90cm mark. Fix this loop with another piece of masking tape.
   2. Attach the pendulum bob at the centre of the string – so that the centre of gravity of the bob is 15cm below the point of suspension (as shown in the figure below.)
      
      Figure 1
2.                          
   1. Measure the angle ........................................1/2 mk
   2. Pull the pendulum bob towards you through a small distance release it and measure time “t” for 10 oscillations......................................................1/2 mk
   3. Remove the masking tape slide the loops to the 12cm and 88cm marks. Refix the masking tape. Measure the angle and time“t” as before
   4. Repeat (iii) above with the loops at 15cm and 85cm, 20cm and 80cm, 25cm, and 75cm. 30 and 70cm, 35cm and 65cm marks.
   5. Enter all your results in the table below.
      

      	10 and 90	12 and 88	15 and 85	20 and 80	25 and 75	30 and 70	35 and 65
      2θ
      θ0
      Cos θ0
      Time for 10 oscillations  t (s)
      Periodic time T(s) T = t (s)      10
      T2(S2)

      (10mks)
3.                              
   1. Plot a graph of T²(y-axis) against cos θ (5mks)
      
   2. Determine the value of T² at the point where the graph intercepts the y – axis. (1mk)
   3. Given that the value of T² at the point A where the graph cuts the y – axis is given by
      A = 0.6π² , use your result in (ii) above to determine the value of K. (3mks)
             K

Question 2
Q2. You are provided with the following apparatus

• A voltmeter
• An ammeter
• A wire x mounted on a metre rule
• 6 connecting wires with crocodile clips
• Micrometer screw gauge
• A switch
• A jockey
• One new dry cell and a cell holder.

Proceed as follows: 

1. Connect the apparatus provided as shown in the circuit below.
   
2. With the crocodile clip at L = 10 cm, close the switch S and record the ammeter and voltmeter reading.
   I = ________________________ A ½ mk
   V = ________________________V ½ mk
3. Repeat the procedure in (b) for other values of l = 15cm, 20cm, 25cm, 30cm, 35cm and recordthe readings in the table below
   

   Length. L. (cm)	10	15	20	25	30	35
   Voltmeter reading , V (volts)
   Ammeter reading , I(A)

   (5mks)
   Plot a graph of potential difference, V(y-axis) against the Current I. (5mks)
   
4. Determine the slope of the graph (2mks)
   Given that V= E – I r, use your graph to determine the value of;
   1. E (1mk)
   2. r (1 mk)
5. Measure the diameter d of the wire x using the micrometer screw gauge.
   d = ___________________________ mm ½ mk
         ____________________________m (1/2 mk)
6. Dismantle the apparatus and set up the circuit as shown below.
   
7. Close the switch S and record the ammeter and the voltmeter readings
   I = __________________________ A
   V = __________________________ V (1mk)
   Hence find R, the resistance of the wire x.
   R = ___________________________ Ω (1mk)
8. Given that R = 4ρ
                          πd² determineρ (2mks)

MARKING SCHEME

Question 1

1.                                                
   

   	10 and 90	12 and 88	15 and 85	20 and 80	25 and 75	30 and 70	35 and 65
   2θ	144	143	117	94	76	57	43
   θ0	72	71.5	58.5	47	38	28.5	21.5
   Cos θ0	0.3090	0.3173	0.5225	0.6820	0.7880	0.8788	0.9304
   Time for 10 oscillations  t (s)	9.94	11.00	12.13	12.97	13.91	14.36	14.65
   Periodic time T(s)	0.994	1.100	1.213	1.297	1.391	1.436	1.465
   	0.988	1.21	1.47	1.68	1.93	2.06	2.15

   
2. Determine the value of T2 at the point where the graph intercepts the y – axis. (1mk)
   4.0 X 10^-1 S² (0.4 S²)
3. Given that the value of T2 at the point A where the graph cuts the y – axis is given by
   A = 0.6π², use your result in (ii) above to determine the value of K. (3mks)
           K
   0.4 = (0.6 X 3.142)/ K
   K = (0.6 X 3.142)/ 0.4
   K =1.8852/0.4
   K = 4.713          Deny 1mk if the answer is not atleast to 3 d.p.

Question 2
d) Table m I =0.44 A
V= 1.0V

e) slope = ΔV    =1.3 – 1.1     = 0.2 V/ A
                 ΔI     0.24 – 0.36    - 0.12
= - 1.67 V/ A
f) From V = E- Ir V = -(r) I + E

1. E vertical intercept
   E = 1.52V ( students values)
2. Slope = - r from the graph
   - 1.667 = -r
   r =1.667Ώ

g) d = 0.28 mm ± 0.01mm
=0.00028 or 2.8 x 10-4m
c) F = 1.0 A
V = 0.04 V R = 0.04 = 0.04 Ώ
                          1.0
j) R = 4ρ          ρ = Rπd²
          πd² 4
ρ = 0.04 Ώ ( 0.00028)²
                    4
ρ =( 7.84x 10^-10) Ώ m

CONFIDENTIAL

QUESTION ONE
Each candidate will require:

• Two retort stands
• Two clamps
• Two bosses
• 120cm long Inextensible thread
• 20cm Inextensible thread
• One pendulum bob
• One stop watch
• Each student to bring a complete geometrical set
• One metre rule
• One half metre rule
• Masking tape

Question 2

• a nichrome wire x, 1m long mounted on mm scale and labeled PQ at the ends (SWG 28)
• a dry cell
• a switch
• a voltmeter ( 0 – 3v)
• an ammeter (0- 1A)
• a cell holder
• eight connecting wires ( 4 with crocodile clips attached to the ends).
• A micrometer screw gauge (can be shared)