Physics Paper 3 Questions and Answers - Form 3 End Term 2 Exams 2023

INSTRUCTIONS TO CANDIDATES

• Answer all questions in the spaces provided in the question paper.
• You are supposed to spend the first 15minutes of the 2 ¼ hours allowed for the paper reading the whole paper carefully.
• Marks are awarded for clear record of the observations actually made, their suitability and accuracy.
• Candidates are advised to record their observations as soon as are made.
• Mathematical tables and calculators may be used.

QUESTION 1

You are provided with the following apparatus

• A metre rule
• A cotton or a silk thread
• A stop watch or stop clock
• A 50g mass
• Four pieces of wood

Proceed as follows:

1. Measure accurately 1 metre of thread and cut it leaving an allowance of 50cm on either end. Mark the centre of the thread
2. Clamp the thread between two retort stands and suspend a 50g mass at the same level 55cm above the bench, as shown below.
   
3. By moving one end of the retort stands, adjust d to value of 40cm.
4. pull the mass slightly in a direction parallel to xy then release it to oscillate. Record the time t,for 20 oscillations.
5. Repeat the procedure (c) and (d) with other values of d, increasing at intervals of 5cm and complete the table below. Where T is the periodic time.
   

   d(cm)	40	45	50	55	60	65	70	75	85
   t(s)
   T(s)
   T2(s2)
   d2(cm2)

   (7mrks)
6. plot a graph of T² against d² (5mrks)
7. Determine the slope of your graph.(3mrks)
8. Given thatT² = 3d² + C using your graph determine the values.
                            m
   1. M (3mrks)
   2. C (2mrks)

QUESTION TWO

PART A

You are provided with the following :

• Vernier caliper
• Micrometer screw gauge
• Masses;two 10g,20g,50g and 100g
• A helical spring
• Metre rule or half metre rule

Proceed as follows

1. Determine the number of complete turns of the helical spring.
   N=……………………………………………….(1mrk)
2. Measure the external diameter of the spring using the vernier calipers
   D=……………………………………m (1mrk)
3. Use the micrometer screw gauge to determine the diameter of the wire of the spring.
   D=……………………………………m (1mrk
4. Determine the value of M  N = 0.4D     (2mrk)
                                                     dM
5. Suspend the helical spring vertically alongside the clamped half metre rule as shown in figure 1below.Determine the length L_o,of the spring before loading it.
   L_o=………………………cm
   
6. load the spring with a mass of 20g and determine the new reading on L) record this in the table below. Calculate the extension e=L−L_o due to the mass of 20g and record the value in the table given below. Repeat step f for other masses and complete the table.
   

   Mass (g)	0	10	20	30	40	50	60	70	80	90	100
   Weight (N)
   Reading (L)cm
   Extension e(cm)
   1/e (cm−1)

7. Plot a graph of weight (N) against 1/e (cm^-1) (5mrks)
8. Determine the slope (s) of the graph at a mass of 45g (3mrks)
9. Given that M = − 255T   
                             (S+60)²
   Determine the value of T where S is the slope at 45g (3mrks)

CONFIDENTIAL

Each candidate should be provided with the following apparatus.

Question 1

• Two retort stands , 2 clamps and 2 boss heads.
• A metre rule.
• A cotton thread (110cm long).
• A stop watch or stop clock.
• 4 pieces of wood (3cm x3cmx1cm).
• A 50g mass.

Question 2

• Vernier calipers (To be shared).
• Micrometer screw gauge (To be shared).
• Masses two 10g, 20g, 50g and 100g.
• A helical spring.
• Metre rule or half metre rule.

MARKING SCHEME

TABLE

(7mrks)

Row 2(t-value)
values correct -0mk
2-3 values correct 1mk
4-5 values correct 2mks
6-7 values correct 3mks
8-9 values correct 4mks

g) slope = ΔT² = (1.44−1.96) 1mrk
                 Δd²     (4900−2500)

h)( i ) T² = 3d² +C
                   M

3  = −0.00022 s²/cm² 1mrk
M
M =      3       1mrk
       0.00022

=−13846.15cm²/s² 1mrk
(ii) C=y – intercept 1mrk
Y intercept=2.55s²
C=2.55s² 1mrk

QUESTION 2

PART A

1. N=83 1mrk
2. D=0.0116m(4 d.p) ± 0.0002 1mrk
3. d=6.3x10^-4m 1mrk
4. N= 0.4D ½ mrk
             dM
   m= 0.4D =   0.4x0.0116     1mrk = 0.0887 4 d.p ½ mrk
           dN      6.3x10⁻⁴x8³
5. L_o = 50.0
6.   

   Mass (g)	0	10	20	30	40	50	60	70	80	90	100
   Weight (N)	0	0.1	0.2	0.3	0,4	0.5	0.6	0.7	0.8	0.9	1.0	✔1mk
   Reading (L)cm	50	51.2	52.4	53.6	54.8	56.0	57.2	58.4	59.6	60.8	62.0	✔1mk
   Extension e(cm)	0	1.2	2.4	3.6	4.8	6,0	7.2	8.4	9.6	10.8	12.0	✔1mk
   1/e (cm−1)	0	0.8333	0.41666	0.2777	0.2083	0.1666	0.1389	0.1190	0.1042	0,0926	0.0833	✔1mk

7.  
   • Scale=1mk –Appropriate scale
   • Axes =1mk-well labelled
   • plots =2mks 8-11 plots correctly plotted
     4-7 correctly plotted 1mk
   • Smooth curve-1mrk
8. slope 5.5 − 3.5  =  2  = 2.5cm 1mrk
             2.2 −  1.4   0.8
9. T = m(5+60)² 1mrk
            −255
   T = 0.0887(2.5+60)² 1mrk =1.3588N²cm² 1mrk
                    −255