PHYSICS PAPER 2 - KAPSABET BOYS 2019 TRIAL MOCK EXAMINATION

SECTION A (25 MARKS)
ANSWER ALL THE QUESTIONS IN THE SPACES PROVIDED

1. Figure 1 below shows two plane mirrors inclined at an angle x from each other. A viewer counts a total of seven images by looking directly from the object O.

Determine value of angel x.                  (2mks)
1. A charged metal sphere is connected to an uncharged electroscope as shown in the figure 2 below. State and explain the observations made. (2mks)
1. A metre rule is suspended by a thread such that it in equilibrium balanced by a permanent magnet attached to the metre rule and some weight as shown in figure 3 below.

If the soft iron is fixed to the bench, state and explain the effect on the metre rule when the switch is close.                                                                                                   (2mks)
1.
1. Explain why convex mirrors are preferred to plane mirrors as vehicle side mirrors.    (1mk)
2. A part from images being formed behind the mirror, state any other two similarities of images formed by a plane mirror and a convex mirror. (2mks)
1.
1. Differentiate between polarization and local action in a simple cell (2mks)
2. State the use of manganese IV oxide in a dry cell (1mk)
1. Other than progressive waves travelling in opposite direction at the same speed, state any other two conditions necessary for the formation of stationary (2mks)
1. A gun is fired and an echo heard at the same place 0.6s later. How far is the barrier, which reflected the sound from the gun? (Speed of sound in air=330ms-1 (3mks)
1. In an attempt to make a magnet, a student used the double stroke method as figure 4 shown below. (2mks)

State the polarities at the ends A and B
1.
1. The figure 5 below shows an electromagnetic relay.

Explain what happens when the switch is closed.                                                      (2mks)
1. A current of 12A flows through a circuit for 2.5 minutes. How much charge passes through the circuit. (2mks)
1.
1. Define term light (1mk)
2. Other than the image being real, state any other characteristics of the images formed by pin-hole camera (1mk)

SECTION B(55MARKS)

ANSWER ALL THE QUESTIONS IN THIS SECTION IN THE SPACES PROVIDED

1.
1. A student stands some distance from a high wall and claps his hands
1. What two measurements would need to be made in order to determine the speed of sound? (2mks)
2. Describe how you would make use of these measurements             (2mks)
3. The speed of sound in air is 330m/s. How far from the wall would you stand? Choose an answer from the following distances 10m, 200m,500m. Give reasons why you did not choose each of the other two distances. (2mks)
2. The balloon filled with carbon dioxide can act like a lens and focus sound from a loud speaker. On to the microphone, Figure 6 show waves produced by loud speaker moving toward the balloon.

1. Complete the diagram to show what happens to the sound waves when they have passed through the balloon and moves towards the microphone.             (2mks)
2. The loud speaker is now moved toward the balloon. This results in less sound at the microphone. Explain why there is less sound at the microphone (1mk)
3. The frequency of the sound emitted by the loud speaker is 1020Hz. Calculate the wavelength of the sound wave in air where its velocity is 340m/s                                  (2mks)
1.
1. Define critical angel (1mk)
2. Figure 7 below shows a ray of light incident on the face of a cube made of glass reflactive index 1.50

Calculate
1. The angle r: (2mks)
2. The critical angle for the glass air interface (2mks)
3. The figure 8 below shows a ray of light incident on a glass prism. Given that the critical angle for the grass is 39o, sketch on the diagram the path of the ray through the prism. (2mks)
1.
1.
1. Definecapacitance of a capacitor and state its S.I unit (2mks)
2. State any two factors that affect the capacitance of a capacitor
3. The figure 9 below shows three capacitors connected between two points A and B.
(3mks)
Determine the capacitance across AB
4. Sketch a simple diagram that contains a capacitor, a two way switch, and a load resistor that can be used for charging and discharging a capacitor. (3mks)
1.
1. State Ohm’s law (1mk)
2. A wire was connected to a battery and was found that the energy converted to heat was 30J when 20C of charge flowed through the wire in 5 seconds. Calculate;
1. The p.d between the ends of the wire (2mks)
2. The current flowing through the wire (1mk)
3. The resistance of the wire                                                                                               (2mks)
4. The average power development in the wire                                                               (2mks)
3. The graph below shows results obtained in an experiment the emf (E) and the internal resistance, r, of a cell. Given that the equation of the graph is E = r + 1

Use the graph to determine the values of:-
Given that the equation of the graph is 1
Use the graph to determine the values of:=
1. E (2mks)
2. R
1.
1. Distinguish between stationery waves and progressive waves. In terms of their propagation                                                                                                       (2mks)
2. The figure 10 represents an oscillation taking place at a particular point while a wave in a gas passes the point. The vertical axis is labeled displacement.

1. Explain what is meant by displacement in this context. (1mk)
2. From the figure determine
1. The period (1mk)
2. The frequency (1mk)
3. Calculate the wavelength of the sound wave in the figure. Take the velocity of sound in the gas to be 340m/s (3mks)
4. State two factors that can increase the speed of sound in solids (2mks)

MARKING SCHEME

1. Let the angle be x
360° -1 =7V1;
360° = 8
8 x= 360° V1;
X = 45° ~1;
1. The leaf diverges (1mk) Negative charges from electroscope flows to the sphere leaving +ve charges on the electroscope thus there is divergence. (1mk)
2. The rule moves anticlockwise, the soft iron core gets magnetized with the upper end having a south pole and hence attracts the north pole of the magnet.
3.
1. convex mirrors have a wider field of view V1
2. -- the images are virtual 1 - the images are erect/upright 1
4.
1. Polarization is the formation of hydrogen bubbles on the anode (copper plate) while local action is the eating away of the zinc plate by acid
2. Depolarizer / reduce polarization ✓ 1 any one oxidizes hydrogen to water
5. - Must have the same amplitude,
Must have same frequency;
6. Distance to barrier x m
Dist covered by sound 2 x 1 Distance = velocity x time;
2 x = 330 x 0.6V 1 x= 330 x 0.6
2x = 99m
1. A- south Pole(1mk)
B - South pole(lmk)
2. Current flows in the circuit and the electromagnet gets magnetized V attracts A which in turn moves up to establish the contacts. This completes the bell circuit hence the bell ring
3. Q = It
= 12 x 2.5 x 60V 1
= 1800CV
4.
1. Light is a form of energy that enables people and animals to see and plants to manufacture their own food through photosynthesis
2. images formed are inverted upside down SECTION B.
1. Time taken for n number of claps. The claps should concide with the echos;
1. The distance between the civil and walls;
2. Sound has to travel to the walls and reflected back to the coil Distance travelled is 2d; For n claps there will be n echoes; Total distance travelled = n x 2d
2nd;
2nd Speed of sound = 2nd/t
3. 200m;
-10m is short distance and timing will be inaccurate;
-500m is too long for sound to travel through and be reflected back. Energy will have been lost along the way
1. When the sound goes through the balloon it is focused to one point, hence changing the position the sound becomes less; (refracted)
V = f2
340 = 1020 x 1; (iii), 340 2 =
1020 = 0.3333m;
1. Critical angel is the angle of incidence in the denser medium for which the angle of refraction in the less dense medium is 90
2.
1. Sin i =n= Sin r = Sin 30 = 0.5 = 0.3333 Sinr
1.5
1.5 Sin r = 0.3333 r= Sin r0.3333 = 19.47
232/2
(1mk)
2. sin c = 1/n = c=sin ('/n)
= sin (4/1.5) = 41.81
100
50 CD50 74040
1000
(1mk)
5.
1. Its unit is the farad; (1mk)
2. Separation of plates
3. Dielectric material - Area of the plates
3mks
4. Series arrangement
1 = 1+1= īĀ 2 4(1mk) C=uf Imk Parallel arrangement
x2 = auf Imk = 2.667 x 10-6F 1mk
3mks any
Gapacitor
Two-wayo Switch
1.
1. It states that the p. d in a circuit is directly proportional to the current provided,
temperature and other physical conditions are kept constant. (lmk)
2.
1. E=IVt
E = QV
- V=E/Q
=30/20
1.5 V
2 mks
2. Q = It
20= I x 5
I= 4A
2mks
3. V = IR
1.5 = 4 x R
R=0.37512
2mks
3.
1. y=Mx+C :C= 0.65 (1mk)
E = 1.538 V (1mk)
E=1 0.65
2mks
2. M=(2-2300009)(1mk)
= 0.8(Imk)
M= = 0.8 r= (0.8 x 1.538) :: r= 1.2304 s2 (1mk)
1.
1. Stationary waveforms do not move through the medium and therefore energy is not transferred from the source to some point awayự 1
Progressive waveforms move through the medium away form its source and therefore energy is transferred from the source to some point away~ 1
1. This is the maximum position of the particles from the mean or disturbed position
2.
1. I. T = 2.0s
2. f = 1 = 0.5Hz
2.  V = 2f2 = V 1
2 = 680mV 1
3. Increase density of solid 1
Reduce temperature of solid