Physics Paper 1 Questions and Answers - Bungoma Diocese Mock Exams 2021/2022

INSTRUCTIONS TO STUDENTS

Attempt ALL questions in sections A and B.
All your answers must be written in the spaces provided in this question paper.
All working must be clearly shown
Non programmable silent electronic calculators and KNEC mathematics table may be used except where stated otherwise

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

Figure 1 below shows a scale of vernier calipers when measuring the width of a meter rule.

What is the actual width of the meter rule if the calipers has a zero error of + 0.6mm.? (2mks)
A clinical thermometer has a constriction in the bore just above the bulb. State the use of the constriction. (1mk)
Figure 2 below shows air trapped by a column of t6he mercury in a U-tube . The atmospheric pressure is 76 cm Hg.

At what pressure in mmHg is the enclosed air? (3mks)
A girl of mass 50 Kg runs up a flight of height 4m in 4 seconds . Calculate the power she developed in this time (2mks)
Name the transducer in the following energy conversions.
1. Kinetic to electrical (1mk)
2. Solar to heat (1mk)
Figure 3 below shows dots produced on a tape pulled through a ticker timer by a moving body.

The frequency of the ticker –timer is 50 Hz. Calculate the acceleration of the body. (3mks)
Figure 4 below shows an ammeter used to measure current through the conductor .The student used the lower scale.

State the reading from the meter (1mk)
Figure 5 below shows a uniform rode AE which is 40 cm long. It has a mass of 2Kg and pivoted at D. If 2N is acting at point E , and 30N force is passed through a frictionless pulley.

Find the force X acting at end A. (3Mks)
Convert -200°C into Kelvins (1mk)
Figure 6 below shows two identical springs constant 3N/cm supporting a load of 30N.

Determine the extension of each spring (3mks)
Explain why a bus should not carry standing passengers. (1mk)
State TWO reasons mercury is preferred as a barometric liquid and not water . (2mks)

SECTION B (55MARKS)
Answer all questions in this section

1. Define the term efficiency as used in machines . (1mk)
2. Figure 7 below shows the cross –section of a wheel and axle of radius 6.5 cm and 1.5 cm respectively used to lift a load. Use it to answer the question that follow.
  
  Determine the
  1. Mechanical advantages (M.A) of the system (2mks)
  2. Velocity ratio (V.R) of the system (2mks)
  3. Efficiency of the machine (2mks)
  4. Give one reason why the above machine is not 100% efficient (1mk)
3. State the law of conservation of energy (1mk)
1. In inelastic collision , kinetic Energy is lost .Explain . (1mk)
2. A Trailer of mass 30 tonnes travelling at a velocity of Km/ her rams onto a stationery bus of mass 10 tonnes . The two move together after impact. Determine the common velocity at which they move after impact. (3 Mks)
3. A stone is thrown vertically upward with an initial velocity of 30 M/s
  1. Determine the maximum height reached. (2mks)
  2. Time taken to come back to the point of projection (2mks)
4. The figure 6 below shows a body being pulled by a constant force of 10N for 4m over wooden surface . The co- efficient of friction is 0.03.
  
  Find the acceleration of the body (3mks)
1. State Hooke’s law (1mk)
2. A graph of force (y-axis) against (x-axis) is provided. Use it to answer questions below.
  
  From the graph determine;
  1. Work done in stretching the spring by 3cm. (3mks)
  2. Spring constant .Give your answer in SI Units. (3mks)
  3. State two factors that affect the spring constant. (2mks)
1. Give reason why ink is likely to ooze a pen when one is up in an airplane. (1mk)
2. The figure below is a simple hydraulic machine used to raise heavy loads.
  
  Calculate;
  1. The pressure exerted on the oil by the force applied at A (2mks)
  2. The load raised at B (2mks)
  3. Give two properties which make the oil suitable for use in this machine . (2mks)
3. The barometer reading at the base of the mountain is 60cm/ Hg while at the top is 50 cm/Hg. If the densities of air and mercury are 1.25kgm^-3 and 13,600kgm^-3 respectively. Calculate the height of the mountain. (3mks)
1. Distinguish between streamline and turbulent flow. (2mks)
2. Figure below shows two light sheets of paper arranged as shown
  
  Explain the observation made when air is blown at the same time at point A and B. (2mks)
3. Figure 12 below shows an incompressible fluid moving through a tube of varied cross-section area. If the area of the small tube is 0.05m², Calculate the area of large tube in cm². (3mks)
4. State the Bernoulli’s principle (1mks)
5. State any TWO assumptions made when deriving the equation of continuity (2mks)
1. State the principal of moments (1mk)
2. A uniform metal strip is 3.0cm wide, 0.5 cm thick and 100 cm long. The density of the metal is 2.7 g/cm³. Determine
  1. The weight of the Metal strip. (2mks)
  2. The strip is placed on a pivot and kept in equilibrium by forces in the figure below.
  3. Determine the value of F . (3mks)

MARKING SCHEME

SECTION A

MSR = 6.90cm
VSR = 0.04cm
= (6.90+ 0.04) cm
Actual width = 6.94cm-0.06
= 6.58cm 2 marks
It prevents the return of the mercury to the bulb when the thermometer is removed from the body to the surrounding
1mark
Pressure = Press. Due to atm. + press. due to liquid column
= (76+50) cmHg
= 126cmHg OR 1260mmHg 3 marks
Power = work done = mgh
Time Time
Power = 50 x 10 x 4
4
Power = 500W 2 marks
1. Dynamo 1 mark
2. Solar panel 1 mark
V = 5 = 250 cm/s
0.02
U = 2 = 100m/s
0.02
a= v−u
t
a = 250 −100
0.06
a = 2500cm/s² or 25cm/s² 3 marks
Reading =1.35 A 1mark
30 x 20 + 10 x 2 = 30 x +10W
600 + 20 =30X +200
620 = 30X +200
X = 14N 3MKS
−200 + 273=73K Working must not be shown 1 marks
e = F
e = 30
2×3
e =5cm 3marks
Standing passengers raise the center of gravity making the bus unstable
- Mercury has a higher density than water
- Mercury does not stick on walls of the glass 2mks

SECTION B

1. Efficiency is the ratio of work done on the load(work output) to the work done by the effort(work input) expressed as a percentage 1mk
2. 1. MA = L
    E
    MA= 150
    50
    = 3 2mks
  2. VR = 2πR
    2πr
    VR = 2π x 6.5
    2 π 1.5
    = 4.333 2mks
  3. efficiency = MA X100
    VR
    efficiency = 3 x 100
    4.333
    = 69.23% 2mks
  4. the friction between the moving parts 1mk
3. The sum of kinetic energy and potential energy of a system is constant
  Or
  Energy can neither be created nor destroyed but can only be changed from one form to another 1mk
  9 marks
1. The bodies undergo deformation
  OR
  Some of the energy is transformed to heat, sound or light 1mk
2. M₁v₁ + m₂v₂ = v(m₁ + m₂)
  30000 x 20 + 10000 x 0 = v(30000 + 10000)
  600000 = v(40000)
  V = 15m/s 3mks
3. 1. ^hmax = u²
    g
    ^hmax = 30²
    10
    = 90m 2mks
  2. T = 2u
    g
    T = 2 x 30
    10
    = 6s 2mks
4. F_r = µR
  F_r = 0.03 x 5x 10
  =1.5N
  Resultant force = 10 − 1.5
  = 8.5N
  F = ma
  8.5 = 5a
  α = 1.7m/s² 3mks
  11mks
1. For a helical spring or any other elastic material, extension is directly proportional to the stretching force provided the elastic limit is not exceeded 1mk
2. 1. work done = area under the graph
    Work done = ½ Fe
    Work done = ½ x 6 x 0.06
    = 0.18j 3mks
  2. spring constant = gradient of the graph
    = Δ force
    Δ Extension
    = 6 − 0
    0.06 − 0
    = 100N/m 3mks
  3. - Nature of the material of the spring
    - Thickness of the wire of the spring
    - The diameter of the spring
    - The number of turns per unit length 2mks
1. There is low atmospheric pressure hence the ink pressure in the pen is higher, forcing the ink out 1mk
2. 1. p = force
    Area
    p = 120
    0.006
    p = 20000 pa 2mks
  2. 20000 = F
    0.5
    Load = 10000N 2mks
  3. - Oil is incompressible
    - The oil does not corrode the parts the machine
    - Have a high boiling point and a low freezing point 2mks
3. Pressure due to air column = Pressure difference
  h_aę_ag = h_mę_mg
  h_a = hₘęₘ ęa
  ha = 0.1x13600
  1.25
  = 1088m 3mks
  10mks
1. Streamline flow is a flow in which all particles of the fluid at a point in a tube of flow are travelling at the same velocity and same direction while turbulent flow is a flow in which particles at a point move with different speeds and in different direction. 2 mks
2. The papers move away from each other, the fast moving area reduces the pressure; the atmospheric pressure in between the papers pushes them apart 2 mks
3. A1v1 = A2 V2
  A1 = 0.056 X 2.5
  0.6
  = 0.233cm² 3mks
4. Provided the fluid is non - viscous, incompressible and flowing steadily, an increase in speed of the fluid produces a corresponding decrease in pressure. 1 mks
5. 1. the fluid in incompressible
  2. the fluid is non - viscous
  3. the flow is streamlined Any 2 x 1 = 2mks
    10 marks
1. For a system in equilibrium, the sum of clockwise moments must be equal to the sum of ant - clockwise moments at a point of support.
2. 1. w = 0.03 x 0.005 x 2700 x 10
    W = 4.05N 2mk
  2. Sum of clockwise moments - sum of the anticlockwise moments
    20 x F = 15 x 4.05
    F = 3.0375 N 3mks
    06 marks