PHYSICS
PAPER 1
TIME: 2 HOURS.
Instructions to candidates
 Answer ALL the questions
 This paper consists of TWO Sections: A and B.
 ALL working MUST be clearly shown.
 Mathematical tables and electronic calculators may be used.
SECTION A (25 MARKS)
 The masses of equal volumes of a certain liquid and water was found to be Mand Mw respectively. Given that the density of water is 1/g/cm3 express the density of liquid in terms of M_{l} and M_{w} (2mks)
 Fig 1 shows a screw use to fix pieces of wood. Explain how a metre rule can be used to find the pitch of the screw. (2mks)
 The figure below shows an object being acted on by two forces F_{1} and F_{2}Draw a force F_{3} that has same effect on the body as the two forces (2mks)
 The reading on a mercury barometer at a place is 700mm. What will be the pressure in N/M^{2} if density of mercury is 13600kg/m^{3} (3mks)
 Steam pipes are constructed with bond at some point of the pipe
State the use of the band  State special features in a clinical thermometer and explain how these features makes it measure temperature conveniently (4mks)
 Two metal rods of same material, same length and same crosssectional area are used to transfer heat from steam to ice as shown below. Metal A is not lagged but B is lagged. Sketch two graphs in same axis to show how temperatures and .......... between hot end and cold end for the two metals (2mks)
 What is the reading on vernier calipers shown below. (1mk)
The set up above shows a metre rule in equilibrium. Given that the rule is uniform, determine its weight (3mks) A spiral spring of spring constant 20N/M is composed by 10cm. Its released to push a mass of 20g horizontally find the speed at which the mass start moving. (3mks)
 The figure below shows a graph of velocity against time for a moving body Describe the motion of the body during the 10 seconds (2mks)
SECTION B: 55 MARKS
 Bowman's motion of smoke particles can be studied by using the apparatus show below.
 Explain the role of the smoke particles, lens and microscope in the experiment (3mks)
 State and explain what kind of motion is observed within the smoke cell (2mks)
 State what will be observed if the smoke cell is kept in a very cold environment and the experiment repeated (1mk)
 Explain briefly why liquids have constant volumes but no constant shapes (2mks)
 Compare the motion observed on smoke in smoke cell with what would be observed with dust particle suspended in water and viewed with a powerful microscope (2mks)

 Define the term specific latent heat of vaporization of a substance. (1mk)
 An immersion heater rated 15W is used to heat a liquid in an open beaker. The beaker contains 300g o liquid. After the liquid boils, the heater is left on for 10 minutes before being switched off. The mass of the liquid is found to have reduced to 296.5g.
 Determine the heat supplied by heater within the 10 minutes of boiling. (3 mks
 Determine the specific latent heat of vaporization of the liquid. (3 mks)
 Explain why this method of determination of latent heat of a substance may not

 State the archimede's principle. (1 mk)
 A rectangular block of crosssectional area of 0.08m^{2} s immersed in a liquid of density 1200kg/m^{3}. The top and lower surfaces of the block are 20cm and 80 cm below the surface of liquid respectively.
 Determine the downward force on the top surface of the block. (3 mks)
 Find the upward force on the lower surface of the block.(3mks)
 Calculate the upthrust on the block.
 Explain why bodies in circular motion undergoes acceleration even when the speed is constant (1mk)
 A particle moving along a circular path of radius 5cm describes an arc of length 2 cm every second. Determine
 Its angular velocity
 Its periodic time (2 mks)
 Number of evolutions per second (1 mk)
 A stone of mass 40g is tied to the end of a string 50cm long and whirled in vertical circle at 2 revolutions per second; calculate the maximum tension in the string. (3 mks)

 A liquid if flowing though a tube of different crosssectional areas A_{1}, A_{2} and A_{3} with velocities V_{1}, V_{2} and V_{3} respectively. (2 mks)
 The figure below shows a Bunsen burner is operation with air hole open
 Explain how air is drawn into the barrel when the gas supply is opened. (2 mks)
 State the purpose of metal ring. (1 mk)
 A pipeline has 15cm diameter to one point and 7.6cm diameter at another point. If the speed of water in the wider section is 1.2m/s. Determine
 Speed of water in narrow section (3 mks)
 Rate of discharge (2 mks)

 Define the term absolute zero temperature (1mk)
 A mass of a gas was put in a container whose one end was closed with a movable piston. The temperature of the gas was gradually changed while the pressure was held constant. The values of volume at different temperatures were noted. The graph below shows the volume against temperature for the gas.
 State the law that relates the volume and temperature of the gas as shown on the graph above. (1mk)
 Given that PV=0.8317 where P is the pressure of the gas, determine the value of P (2mks)
 A tank contains a gas at pressure of 8 x 10^{5} pa and a temperature of 288K. The gas is heated until its pressure rises to 8 x 10opa. Find the new temperature of the gas given that the volume is constant. (3mks)
 Using Kinetic theory of matter, explain why, the pressure of a gas rises when volume is reduced (2mks)
MARKING SCHEME
SECTION A (25 MARKS)
 The masses of equal volumes of a certain liquid and water was found to be Mand Mw respectively. Given that the density of water is 1 g/cm^{3} express the density of liquid in terms of M_{l} and M_{w} (2mks)
 V_{L} = M_{L}
d_{L}
And V_{w}= M_{w} = M_{L } = M_{w}
d_{1} d_{L} L
therefore d_{2} = M_{L}
M_{w}
 V_{L} = M_{L}
 Fig 1 shows a screw use to fix pieces of wood. Explain how a metre rule can be used to find the pitch of the screw. (2mks)
 Measure the length of the threads part
 Divide length with no. of threads
 The figure below shows an object being acted on by two forces F_{1} and F_{2}Draw a force F_{3} that has same effect on the body as the two forces (2mks)
 Length = 2.2cm
 Direction and arrow
 The reading on a mercury barometer at a place is 700mm. What will be the pressure in N/M^{2} if density of mercury is 13600kg/m^{3} (3mks)
 P=hdg
=0.7 x13600 x 10
= 95,200
 P=hdg
 Steam pipes are constructed with bond at some point of the pipe
State the use of the band To provide room for expansion
 To provide room for expansion
 State special features in a clinical thermometer and explain how these features makes it measure temperature conveniently (4mks)
 Constriction nholds mercury thread in position when reading are taken
 Scale between 3542range within human body temperature,
 Two metal rods of same material, same length and same crosssectional area are used to transfer heat from steam to ice as shown below. Metal A is not lagged but B is lagged. Sketch two graphs in same axis to show how temperatures and .......... between hot end and cold end for the two metals (2mks)
 What is the reading on vernier calipers shown below. (1mk)
0.50
+ 0.05
0.55cm
The set up above shows a metre rule in equilibrium. Given that the rule is uniform, determine its weight (3mks) Clockwise moment  Anticlockwise moment
0.1w +0.6x1 = 0.4 x 2
W = 0.2 = 2N
0.1
 Clockwise moment  Anticlockwise moment
 A spiral spring of spring constant 20N/M is composed by 10cm. Its released to push a mass of 20g horizontally find the speed at which the mass start moving. (3mks)
 Elastic potential  kinetic energy acquired by mass
Energy in Spring
½ke^{1}  ½mv^{2}20x (0.01)2 = 0.02v2
v= √^{20 x (0.02)2}/_{0.02}= 0.3162m/s
 Elastic potential  kinetic energy acquired by mass
 The figure below shows a graph of velocity against time for a moving body Describe the motion of the body during the 10 seconds (2mks)
 A body projected vertically upwards at 20m/s reaches the highest point and comes back to the point of projection
SECTION B: 55 MARKS
 Bowman's motion of smoke particles can be studied by using the apparatus show below.
 Explain the role of the smoke particles, lens and microscope in the experiment (3mks)
 Smoke particles  reflect light as they move around
 Lens  focuses light into smoke cell
 Microscope  magnifies the smoke particles for easier visibility.
 State and explain what kind of motion is observed within the smoke cell (2mks)
 Smoke particles are seen moving in a continuous random motion, due to combinement by invisible air molecules
 Smoke particles are seen moving in a continuous random motion, due to combinement by invisible air molecules
 State what will be observed if the smoke cell is kept in a very cold environment and the experiment repeated (1mk)
 The random motion of the particles will reduce
 The random motion of the particles will reduce
 Explain briefly why liquids have constant volumes but no constant shapes (2mks)
 Intermolecular distance between liquid molecules is constant at a particular temperature hence constant volume.
 The molecules can easily change positions within the bulk of the liquid hence no constant shape
 Compare the motion observed on smoke in smoke cell with what would be observed with dust particle suspended in water and viewed with a powerful microscope (2mks)
 Higher constant random motion in gone the two weak intermolecular forces.
 Lower constant random motion in liquids due to stronger intermolecular forces.
 Explain the role of the smoke particles, lens and microscope in the experiment (3mks)

 Define the term specific latent heat of vaporization of a substance. (1mk)
 Heat energy required to vapourise a unit mass of a liquid at a constant temperature
 Heat energy required to vapourise a unit mass of a liquid at a constant temperature
 An immersion heater rated 15W is used to heat a liquid in an open beaker. The beaker contains 300g o liquid. After the liquid boils, the heater is left on for 10 minutes before being switched off. The mass of the liquid is found to have reduced to 296.5g.
 Determine the heat supplied by heater within the 10 minutes of boiling. (3 mks)
 Heat = power x time
= 15 x 10 x 60
= 9000 Joules
 Heat = power x time
 Determine the specific latent heat of vaporization of the liquid. (3 mks)
 Heat = Latent heat x mass
9000 = 35 x Lv
1000
Lv = 2.571 x 10^{6}J/kg
 Heat = Latent heat x mass
 Explain why this method of determination of latent heat of a substance may not
 Some heat is absorbed by containee
 Some heat is radiated away during heating
 Determine the heat supplied by heater within the 10 minutes of boiling. (3 mks)
 Define the term specific latent heat of vaporization of a substance. (1mk)

 State the archimede's principle. (1 mk)
 An object partially or fully submerged in a liquid experiences upthrust equal to weight displaced.
 An object partially or fully submerged in a liquid experiences upthrust equal to weight displaced.
 A rectangular block of crosssectional area of 0.08m^{2} s immersed in a liquid of density 1200kg/m^{3}. The top and lower surfaces of the block are 20cm and 80 cm below the surface of liquid respectively.
 Determine the downward force on the top surface of the block. (3 mks)
 F = PxA
= 0.2 x 1200 x 10 x 0.008
= 192N
 F = PxA
 Find the upward force on the lower surface of the block.(3mks)
 Calculate the upthrust on the block.
 Determine the downward force on the top surface of the block. (3 mks)
 Explain why bodies in circular motion undergoes acceleration even when the speed is constant (1mk)
 Bodies moves in constantly changing directions hence acceleration.
 Bodies moves in constantly changing directions hence acceleration.
 A particle moving along a circular path of radius 5cm describes an arc of length 2 cm every second. Determine
 Its angular velocity
 W = ^{θ}/_{t}θ_{1}= arc length = 2 = 0.4
Radius 5
=0.4/1
= 0.4rad/s
 W = ^{θ}/_{t}θ_{1}= arc length = 2 = 0.4
 Its periodic time (2 mks)
 f = w = 0.4 = 0.0637sec
2Π 6.284
T = ^{1}/_{f}
=15.71sec
 f = w = 0.4 = 0.0637sec
 Number of evolutions per second (1 mk)
 no of revolutions/sec=f=0.0637
 no of revolutions/sec=f=0.0637
 Its angular velocity
 A stone of mass 40g is tied to the end of a string 50cm long and whirled in vertical circle at 2 revolutions per second; calculate the maximum tension in the string. (3 mks)
 T = mv^{2} + mg
r
V=2Jrf = 6.284m/s
= 0.04 x 39.4889 +0.4
0.5
= 3.159N
 T = mv^{2} + mg
 State the archimede's principle. (1 mk)

 A liquid if flowing though a tube of different crosssectional areas A_{1}, A_{2} and A_{3} with velocities V_{1}, V_{2} and V_{3} respectively. (2 mks)
 V_{1} 1 = VA = K
A1
V_{2} 1 = V_{2}A_{2} = K
A2
V_{1}A_{1} = V_{2}A_{2}
 V_{1} 1 = VA = K
 The figure below shows a Bunsen burner is operation with air hole open
 Explain how air is drawn into the barrel when the gas supply is opened. (2 mks)
 Air enters the barrel at very high speed creating low pressure within barrel, air of forced in the barrel by atmospheric pressure to occupy the low pressure region
 Air enters the barrel at very high speed creating low pressure within barrel, air of forced in the barrel by atmospheric pressure to occupy the low pressure region
 State the purpose of metal ring. (1 mk)
 To regulate the amount of air entering
 To regulate the amount of air entering
 Explain how air is drawn into the barrel when the gas supply is opened. (2 mks)
 A pipeline has 15cm diameter to one point and 7.6cm diameter at another point. If the speed of water in the wider section is 1.2m/s. Determine
 Speed of water in narrow section (3 mks)
 A_{1}V_{1} = A_{2}V_{2}
0.0176 x 1.2 = 4.536 x V_{2}Therefore V_{2} = 4.655m/s
 A_{1}V_{1} = A_{2}V_{2}
 Rate of discharge (2 mks)
 volume flux = AV = 0.0211m^{3}/s
 volume flux = AV = 0.0211m^{3}/s
 Speed of water in narrow section (3 mks)
 A liquid if flowing though a tube of different crosssectional areas A_{1}, A_{2} and A_{3} with velocities V_{1}, V_{2} and V_{3} respectively. (2 mks)

 Define the term absolute zero temperature (1mk)
 Temperature at which gases molecules ceases to move
 Temperature at which gases molecules ceases to move
 A mass of a gas was put in a container whose one end was closed with a movable piston. The temperature of the gas was gradually changed while the pressure was held constant. The values of volume at different temperatures were noted. The graph below shows the volume against temperature for the gas.
 State the law that relates the volume and temperature of the gas as shown on the graph above. (1mk)
 Charles law  That temperature of a fixed mass of a gas is directly proportional to absolute temperature as long as p is constant.
 Charles law  That temperature of a fixed mass of a gas is directly proportional to absolute temperature as long as p is constant.
 Given that PV=0.8317 where P is the pressure of the gas, determine the value of P (2mks)
 Slope = (5  1.8) x 10^{3} 600  200
8 x 10^{6}m^{3}/K = 0.831
OP
= P = 103Pa
 Slope = (5  1.8) x 10^{3} 600  200
 A tank contains a gas at pressure of 8 x 10^{5} pa and a temperature of 288K. The gas is heated until its pressure rises to 8 x 10opa. Find the new temperature of the gas given that the volume is constant. (3mks)
 P_{1} = P_{2}
T_{1} T_{2}
= 8 x 10^{5}
288
= 8 x 10^{6}
T^{2}
T^{2}  2880Pa
 P_{1} = P_{2}
 Using Kinetic theory of matter, explain why, the pressure of a gas rises when volume is reduced (2mks)
 Number of collisions increases due to decreased volume bence increased pressure.
 State the law that relates the volume and temperature of the gas as shown on the graph above. (1mk)
 Define the term absolute zero temperature (1mk)
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