Free KCSE Physics Topical Questions KNEC Standards

A student set-up the apparatus as shown below to determine the power of an electric heater.

19/10/2021

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A student set-up the apparatus as shown below to determine the power of an electric heater

A student set-up the apparatus as shown above to determine the power of an electric heater

(a)
(i) Other than time, state the measurements that would be used to determine the quantity of heat P absorbed by ice in a unit time (2mks)

Current, voltage (p.d) mass of water collected temperature of the melt

(ii) Complete the circuit to show the connection of the essential circuit components (2mks)

(iii) Describe how the student would proceed to determine P (3mks)

Switch on the current and start the clock simultaneously
Record the steady venus current I and P.d.v
Note the temperature of the melt( should be 0oC)
Weighs the melt to obtain its mass m, collected over a known length of time , t

Apply Ivt=mlf

(iv) Give a reason why P may not be equal to the value indicated by the manufacturer (1mk)

It may not be operating at its optimum conditions of p.d and temperature, T. the heater also absorbs heat

(b) In another experiment, 100g of hot water at 90^oC was mixed with 20g of ice at 0^oC in a lagged plastics colorimeter. After stirring, all the ice melted and the temperature of the mixture was found to be 61.5^oC. Determine the latent heat of fusion of ice (3mks)

(Specific heat capacity of water = 4200Jkg^-1k^-1)

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K.C.S.E Physics Q & A - MODEL 2019PP1QN16

31/7/2020

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K.C.S.E Physics Q & A - MODEL 2019PP1QN16

(a) State the meaning of the term “heat capacity.”
(b) State how pressure affects the melting point of a substance.
(c)Figure 7 shows a set tip of apparatus that may be used to apparatus the specific latent heat of vaporization of steam

(I) Describe how the mass of condensed steam is determined.
(ii) Other than mass and time, state two other measurements that should be taken during the experiment.
(iii) Show how the measurements in (c)(ii) can be used to determine the specific latent heat of vaporization of water.
(iv) State the precaution that should be taken so that the mass of the condensed steam measured corresponds to the actual mass of steam collected during the time recorded in the experiment
(v) State why it is not necessary to measure temperature in in the set up

answers

(a) Heat capacity is the quantity of heat energy required to raise the temperature of a substance by 1K.
(b) - Increase in pressure lowers the melting point while decrease in (1 mark) pressure raises/increases the melting point.
(c) (i) - Measure the mass of the empty beaker M1.
Measure the mass of the beaker plus the condensed steam M2
Get the difference between the two masses (M2 —M1) = M
(ii) - Voltage
Current

(iv) - Start timing when the steam drops start forming out steadily and Stop immediately the beaker is withdrawn.
(V) Steam is produced at boiling point where temperature is constant.

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K.C.S.E Physics Q & A - MODEL 2018PP1QN14

29/7/2020

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K.C.S.E Physics Q & A - MODEL 2018PP1QN14

(a) State two differences between boiling and evaporation.
(b) State three ways in which loss of heat by conduction is minimized in a vacuum flask.
(c) In a certain experiment, 50g of dry steam at 100 °C was directed into some crushed ice at 0 °C. (Latent heal of vaporization of water is 2.26 X 106 Jkg-1, latent heat of fusion for ice is 3.34 X 10⁵ Jkg^-1 and specific heat capacity of water is 4.2 X 10³ Jkg^-1)
Determine the;

(i) quantity of heat lost by steam to change to water at 100 °C.
(ii) quantity of heat lost by water to cool to 0°C.
(iii) mass of ice melted at 0°C.

answers

(a) Boiling takes place at fixed temperature while evaporation takes at all temperatures.
Boiling takes place in the entire liquid while evaporation takes place at the surface.
(b) - Presence of a vacuum.
- Poor conductor material used to make stopper.
- Use of glass (poor conductor).

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K.C.S.E Physics Q & A - MODEL 2017PP1QN11

28/7/2020

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K.C.S.E Physics Q & A - MODEL 2017PP1QN11

A student who wanted to take a bath mixed 4 kg of water at 80 ^oc with 6 kg of water at 20 ^oc.
Determine the final temperature of the water.

answer

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K.C.S.E Physics Q & A - MODEL 2016PP1QN14

27/7/2020

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K.C.S.E Physics Q & A - MODEL 2016PP1QN14

a) Explain why it is advisable to use a pressure cooker for cooking at high altitudes

b) Water of mass 3.0kg initially at 20⁰C is heated in an electric kettle rated 3.0KW. The water is heated until it boils at 100⁰C. (Take specific heat capacity of water 4200Jkg1K^-1. Heat capacity of the kettle = 450JK^-1, Specific latent heat of vaporization of water = 2.3Mjkg^-1)

Determine
(i) The heat absorbed by the water.
ii)Heat absorbed by the electric kettle
iii) The time taken for the water to boil
iv) How much longer it will take to boil away all the water.

ANSWERS

(a) At high altitudes pressure is low so boiling point is low
A pressure cooker increases pressure inside it which raises the boiling point hence faster cooking

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K.C.S.E Physics Q & A - MODEL 2015PP1QN16

24/7/2020

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K.C.S.E Physics Q & A - MODEL 2015PP1QN16

(a) Figure 10 shows an incomplete set up that can be used in an experiment to determine the specific heat capacity of a solid of mass m by electrical method.

(i)complete the diagram by inserting the missing components for the experiment to work.
(ii)Other than temperature, state three measurements that should be taken.
(iii) The final temperature was recorded as O. Write an expression that can be used to determine the specific heat capacity of the solid.
(b) State three ways of increasing the sensitivity of a liquid-in-glass thermometer

answers

(a) (i) ammeter in series
voltmeter in parallel
(ii) ammeter reading (current)
- voltmeter reading (voltage)
-time

(b) reduce the diameter of the bore
use a thin walled bulb
use a liquid with a high expansivity

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K.C.S.E Physics Q & A - MODEL 2014PP1QN17

23/7/2020

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K.C.S.E Physics Q & A - MODEL 2014PP1QN17

(a) A long horizontal capillary tube of uniform bore sealed at one end contains dry air trapped by a drop of mercury. The length of the air column is 142 mm at 17°C.
Determine the length of the air column at 25°C.
(b) The pressure of the air inside a car tyre increases if the car stands out in the sun for some time on a hot day. Explain the pressure increase in terms of the kinetic theory of gases.
(c) In an experiment to determine the specific latent heat of vaporization of water, steam of mass 10g at 100°C is passed into 100 g of water initially at 20°C in a container of negligible heat capacity. The temperature of the water rises to 70°C.
(Take the specific heat capacity of water as 4.2 X 10³ J kg^-1 K^-1(and the boiling point of water as 100°C)
(i) Determine the specific latent heat of vaporization of water.
(ii) State two sources of error in this experiment.

answers

(b) In the hot sun the temperature of the air increases; therefore the speed of the air molecules increases hence the rate of collisions between the molecules and tyre increases; The rate of change of momentum (pressure) of the molecules also increases.

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K.C.S.E Physics Q & A - MODEL 2013PP1QN15

22/7/2020

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K.C.S.E Physics Q & A - MODEL 2013PP1QN15

(a) State the meaning of the term “specific latent heat of fusion”.
(b) Figure 8 shows a set up of apparatus used in an experiment to determine the specific latent heat of fusion of ice.

The following readings were noted after the heater was switched on for 5 minutes:
- mass of beaker = 130 g
- mass of beaker + melted ice = 190 g
(i) Determine the:
(I) energy supplied by the 60 W heater in the 5 minutes.
(II) specific latent heat of fusion of ice.
(ii) It was observed that some of the crushed ice melted even before the heater was switched on. State a reason for this observation.

answers

(a) Quantity of heat required to convert 1 kg of ice at 0 C to water without change in temperature;

(iii) Heat from the surrounding melts the ice;

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K.C.S.E Physics Q & A - MODEL 2012PP1QN17

21/7/2020

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K.C.S.E Physics Q & A - MODEL 2012PP1QN17

(a) Figure 11 shows how an underground room was ventilated. It had two vents, one at A and the other at B. A fire was lit at point C.

Explain what happened to the ventilation when the fire was lit.
(b) Explain how a vacuum flask minimizes loss of heat through radiation.
(c) In an experiment to investigate the unusual expansion of water, a fixed mass of water at O°C was heated until its temperature reached 20°C. On the axis provided, sketch a graph of density against temperature of the water from O °C to 20°C.

(d) An immersion heater rated 2.5 kW is immersed into a plastic jug containing 2 kg of water and switched on for 4 minutes. Determine;
(i) the quantity of heat gained by the water;
(ii) the temperature change for the water;
(take specific heat capacity of water as 42 x 10³Jkg^-1K^-1).

ANSWERS

(a) Fire heats air around region C which expands and becomes less dense;
The less dense air rises up the vent and emerges at A;
Cool (more dense) air moves down the vent at B introducing fresh air into the mine
(b) The flask has double walls which are silverly on both sides the shiny surface is a good reflector of heat;

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K.C.S.E Physics Q & A - MODEL 2011PP1QN17

19/7/2020

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K.C.S.E Physics Q & A - MODEL 2011PP1QN17

(a) When the temperature of water reaches the boiling point, bubbles rise to the surface.
(î) State what is contained in the bubbles.
(ii) State the reason why bubbles rise to the surface only at the boiling point.
(b) Figure 14 shows a graph of vapour pressure against the temperature of water vapour, in a laboratory where a mercury barometer indicates a height of 61.8 cm.

(b) (i) Determine the atmospheric pressure in the laboratory in Nm^-2.
(Take g = 10m/s² and density of mercury = 13600 kg/m³).
(ii) Use the graph to determine the boiling point of water in the laboratory.
(c) In an experiment to determine the specific heat capacity of a metal, a 100g of the metal was transferred from boiling water to a lagged copper calorimeter containing cold water. The water was stirred and a final steady temperature was realized. The following data was recorded.
Initial temperature of cold water and calorimeter = 20°C.
Temperature of boiling water = 99°C.
Final temperature of water, calorimeter and the metal = 27.7°C.
Mass of cold water and calorimeter = 130g.
Mass of calorimeter = 50g.
(Take specific heat capacity of water as 4200Jkg^-1K^-1)
(Specific heat capacity of copper as 400Jkg^-1K^-1).
Use the data to determine:
(i) the heat gained by the water and the calorimeter;
(ii) the specific heat capacity of the metal.
(d) State one possible source of error in the value of the specific heat capacity obtained in the experiment.

answers

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K.C.S.E Physics Q & A - MODEL 2010PP1QN17

19/7/2020

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K.C.S.E Physics Q & A - MODEL 2010PP1QN17

(a) Explain why it is advisable to use a pressure cooker for cooking at high altitudes.
(b) Water of mass 3.0kg initially at 20°C is heated in an electric kettle rated 3.0KW. The water is heated until it boils at 100°C. (Take specific heat capacity of water 4200J kg^-1K^-1, Heat capacity of the kettle = 450JK^-1 , Specific latent heat of vaporization of water = 2.3mJkg-1)

Determine:
(î) the heat absorbed by the water;
(ii) heat absorbed by the electric kettle;
(iii) the time taken for the water to boil;
(iv) how much longer it will take to boil away all the water

answers

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K.C.S.E Physics Q & A - MODEL 2009PP1QN15

17/7/2020

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K.C.S.E Physics Q & A - MODEL 2009PP1QN15

(a) State two factors that affect the boiling point of a liquid
(b) 100g of a liquid at a temperature of 10⁰C is poured into a well lagged calorimeter
An electric heater rated 50W is used to heat the liquid. The graph in figure 8 shows the variation of the temperature of the liquid with time.

(i) From the graph, determine the boiling point of the liquid
(ii) (I) Determine the heat given out the by the heater between the times t= 0.5 minutes and t= 5.0 minutes
(II) From the graph determine the temperature change between the times t = 0.5 minutes and t= 5.0 minutes
(III) Hence determine the specific heat capacity of the liquid
(iii) 1.8 g of vapour was collected from above the liquid between the times t= 6.8 minutes and t= 7.3 minutes. Determine the specific latent heat of vaporization of the liquid

answers

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K.C.S.E Physics Q & A - MODEL 2008PP1QN16

16/7/2020

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K.C.S.E Physics Q & A - MODEL 2008PP1QN16

a) Define the term heat capacity.
b) You are provided with the apparatus shown in Fig. 9 and a stop watch.

Describe an experiment to determine the specific latent heat of steam, l, using the set up. In your answer clearly explain the measurements to be made and how these measurements could be used to determine l.
c) A block of metal of mass 150g at 100⁰C is dropped into a lagged calorimeter of heat capacity 40JK^-1 containing 100g of water at 25⁰C. The temperature of the resulting mixture is 34⁰C. (Specific heat capacity of water=4200JK^-1).
Determine:
(i) Heat gained by calorimeter;
(ii) Heat gained by water;
(iii) Heat lost by the metal block;
(iv) Specific heat capacity of the metal block

answers

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K.C.S.E Physics Q & A - MODEL 2008PP1QN04

15/7/2020

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K.C.S.E Physics Q & A - MODEL 2008PP1QN04

Water is known to boil at 100⁰C. A student heated some water and noticed that it boiled at 101⁰C.

State two possible reasons for this observation.

answer

Atmospheric pressure is higher than normal/ standard or boiling was below
Pressure of impurities

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K.C.S.E Physics Q & A - MODEL 2007PP1QN17

15/7/2020

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K.C.S.E Physics Q & A - MODEL 2007PP1QN17

(a) Define the term specific latent heat of vaporization of a substance
(b) Figure 11 shows the features of a domestic refrigerator. A volatile liquid circulates through the capillary tubes under the action of the compression pump.

(i) State the reason for using a volatile liquid
(ii) Explain how the volatile liquid is made to vaporize in the cooling compartment and to condense in the cooling fins
(iii) Explain how cooling takes place in the refrigerator
(iv) What is the purpose of the double wall?
(c) Steam of mass 3.0 g at 100⁰C is passed into water of mass 400g at 10⁰C. The final temperature of the mixture is T. the container absorbs negligible heat. (Specific latent heat of vaporization of steam = 2260 kJ/ kg, specific heat capacity of water = 4200Jkg^-1K^-1)
(i) Derive an expression for the heat lost by the steam as it condenses to water at temperature T.
(ii) Derive an expression for the heat gained by water
(iii) Determine the value of T

answers

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K.C.S.E Physics Q & A - MODEL 2006PP1QN18

14/7/2020

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K.C.S.E Physics Q & A - MODEL 2006PP1QN18

(a) Define specific latent heat of fusion of a substance
(b) Water of mass 200 g at a temperature of 60⁰C is put well lagged copper calorimeter of mass 80g. A piece of ice at 0⁰C and mass 20 g is placed in the calorimeter and the mixture stirred gently until all the ice melts. The final temperature, T of the mixture is then measured.
Determine
(i) The heat absorbed by the melting ice at 0⁰C.
(ii) The heat absorbed by the melted ice ( water) to rise to temperature T (answer may be given in terms of T)
(iii) The heat lost by the warm water and the calorimeter (answer may be given in terms of T)
(iv) The final temperature T of the mixture (specific latent heat of fusion of ice = 334 000 J kg^-1 ( specific heat capacity of water = 4 200 Jkg^-1 k^-1 Specific heat capacity of copper = 900 J kg^-1)

ANSWERS

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K.C.S.E Physics Q & A - MODEL 2006PP1QN08

14/7/2020

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K.C.S.E Physics Q & A - MODEL 2006PP1QN08

Beaker A contains 200g of water at 0⁰ C while beaker B contains 200g of a mixture of ice and water at 0⁰C. Two identical metal blocks are removed from a hot furnace. One block is dropped into beaker A while the other is dropped into beaker B at the same time.
Explain why more water evaporates from beaker A than from beaker B

answer

. In B some of the heat is used up in melting the ice, while in A all the heat goes to raise the temperature of the water to reach boiling point

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K.C.S.E Physics Q & A - MODEL 2005PP1QN20&21

13/7/2020

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K.C.S.E Physics Q & A - MODEL 2005PP1QN20&21

Fig 11 shows the variation of temperature, with time t, when an immersion heater is used to heat a certain liquid. Study the figure and answer questions 20 and 21.

State the reason for the shape of graph in the section labeled BC
Sketch on the same axes the graph for another liquid of the same mass but higher specific heat capacity when heated from the same temperature.

ANSWERS

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K.C.S.E Physics Q & A - MODEL 2004PP2QN02

12/7/2020

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K.C.S.E Physics Q & A - MODEL 2004PP2QN02

a) In an experiment to determine the power of an electric heater, melting ice was place in a container with an outlet and the heater placed in the ice as shown in Fig. 2. The melted ice was collected.

i) Other than the current and voltage, state the measurement that would be taken to determine the quantity of heat absorbed by the melted ice in unit time.
(ii) If the latent heat of fusion of ice is L, show how measurement in (i) above would be used in determining the power P. of the heater.
(iii) It is found that the power determined in this experiment is lower than the manufacturer‟s value indicated on the heater.
b) Fig 3 shows part of an experimental set up for estimating the diameter of an oil molecule.

i) Describe how the oil patch is formed
ii) In an experiment the diameter a, of the patch was measured to be 200mm for an oil drop of radius 0.25mm. Determine the diameter of the molecule of the oil.

answers

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K.C.S.E Physics Q & A - MODEL 2003PP2QN06

12/7/2020

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K.C.S.E Physics Q & A - MODEL 2003PP2QN06

a) Figure 6 shows a simple set up for pressure law apparatus.

Describe how the apparatus may be used to verify pressure law. Initial reading of pressure and temperatures are recorded.
b) The graph in fig 7 shows the relationship between the pressure and temperature for a fixed mass of an ideal gas at a constant volume.

(i) Given that the relationship between pressure, p, and temperature, T n Kelvin is of the form P = kT+ C where k and C are constants, determine from the graph, values of k and c.
(ii) Why would it be impossible for pressure of the gas to reduced to zero in practice?
(c) A gas is put into a container of fixed volume at a pressure of 2.1 x 105 N/m2 and temperature 27C. the gas is then heated temperature of 327C.
Determine the new pressure.

answers

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K.C.S.E Physics Q & A - MODEL 2003PP2QN03

12/7/2020

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K.C.S.E Physics Q & A - MODEL 2003PP2QN03

a) State what is meant by the term "specific latent heat of vaporization"
b) In an experiment to determine the specific latent heat of vaporization of water, steam at 100C was passed into water contained in a well-lagged copper calorimeter. The following measurements were made;
(i) Determine the:
I Mass of condensed steam
II Heat gained by water
Heat gained by calorimeter

(ii) Given that L is the specific latent heat of vaporization of steam,
I write an expression for the heat given out steam.
II Determine the value of L.

ANSWERS

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K.C.S.E Physics Q & A - MODEL 2003PP1QN28

12/7/2020

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K.C.S.E Physics Q & A - MODEL 2003PP1QN28

A heating element rated 2.5 kW is used to raise the temperature of 3.0kg of water through 500^oC. Calculate the time required to effect this. (Specific heat capacity of water is 4200 J/kgK)

ANSWER

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K.C.S.E Physics Q & A - MODEL 2002PP2QN06

10/7/2020

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K.C.S.E Physics Q & A - MODEL 2002PP2QN06

a) State the law that relates the volume of a gas to the temperature of a gas.
b) Fig 7. shows an experiment set-up that may be used to investigate one of the laws. The glass tube has a uniform bore and it is graduated in millimeter

i) Describe how the experiment was carried out and explain how the results obtained verify the law.
ii) Limitations of the set up are?
c) In an experiment to find the relation between pressure, p, and temperature, of a gas at a constant volume, values of temperature were determined. The results obtained are shown in the graph below.

(i) From the graph, determine the pressure at a temperature of 273K.
(ii) Assuming the relation p/T0+0 = constant holds for this graph determine the value of the constant T0

answers

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K.C.S.E Physics Q & A - MODEL 2002PP2QN04

10/7/2020

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K.C.S.E Physics Q & A - MODEL 2002PP2QN04

a) Fig 5. Shows the variation of temperature, T (0C), with time, t (seconds). When frozen water is heated for sometime

(i) Explain the shape of the curve at the parts labeled AB and C.
(ii) It is observed that when the temperature starts to rise, the volume initially decreases and then increases. State the reason for this observation.
(iii) In the fig. 5 sketch and explain the curve that would be obtained if frozen water was used. (Hint: specific heat capacity for seawater is lower what of fresh water.
(b) Determine the quantity of heat energy required to change 3.0 kg of ice at 0 C to water at 5 °C Specific latent heat of fusion of ice is 3.36 x 10⁵J/kg. Specific heat capacity of water is 4200J/kgK)

answers

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K.C.S.E Physics Q & A - MODEL 2002PP1QN19

10/7/2020

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K.C.S.E Physics Q & A - MODEL 2002PP1QN19

An immersion heater rated 90W is placed is a liquid of mass 2kg. When the heater is switched on for 15 minutes the temperature of the liquid rises form 20°C to 30°C .Determine the specific heat capacity of the liquid. (Assume no heat losses)

answer

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<<Previous

(a) ​(i) Other than time, state the measurements that would be used to determine the quantity of heat P absorbed by ice in a unit time (2mks)

​(ii) Complete the circuit to show the connection of the essential circuit components (2mks)

​(iii) Describe how the student would proceed to determine P (3mks)

​(iv) Give a reason why P may not be equal to the value indicated by the manufacturer (1mk)

(b) In another experiment, 100g of hot water at 90oC was mixed with 20g of ice at 0oC in a lagged plastics colorimeter. After stirring, all the ice melted and the temperature of the mixture was found to be 61.5oC. Determine the latent heat of fusion of ice (3mks)

K.C.S.E Physics Q & A - MODEL 2019PP1QN16

K.C.S.E Physics Q & A - MODEL 2018PP1QN14

(i) quantity of heat lost by steam to change to water at 100 °C. (ii) quantity of heat lost by water to cool to 0°C. (iii) mass of ice melted at 0°C.

K.C.S.E Physics Q & A - MODEL 2017PP1QN11

A student who wanted to take a bath mixed 4 kg of water at 80 oc with 6 kg of water at 20 oc. Determine the final temperature of the water.

K.C.S.E Physics Q & A - MODEL 2016PP1QN14

b) Water of mass 3.0kg initially at 200C is heated in an electric kettle rated 3.0KW. The water is heated until it boils at 1000C. (Take specific heat capacity of water 4200Jkg1K-1. Heat capacity of the kettle = 450JK-1, Specific latent heat of vaporization of water = 2.3Mjkg-1)

K.C.S.E Physics Q & A - MODEL 2015PP1QN16

K.C.S.E Physics Q & A - MODEL 2014PP1QN17

K.C.S.E Physics Q & A - MODEL 2013PP1QN15

K.C.S.E Physics Q & A - MODEL 2012PP1QN17

(d) An immersion heater rated 2.5 kW is immersed into a plastic jug containing 2 kg of water and switched on for 4 minutes. Determine; (i) the quantity of heat gained by the water; (ii) the temperature change for the water; (take specific heat capacity of water as 42 x 103Jkg-1K-1).

K.C.S.E Physics Q & A - MODEL 2011PP1QN17

K.C.S.E Physics Q & A - MODEL 2010PP1QN17

Determine: (î) the heat absorbed by the water; (ii) heat absorbed by the electric kettle; (iii) the time taken for the water to boil; (iv) how much longer it will take to boil away all the water

K.C.S.E Physics Q & A - MODEL 2009PP1QN15

(a) State two factors that affect the boiling point of a liquid (b) 100g of a liquid at a temperature of 100C is poured into a well lagged calorimeter An electric heater rated 50W is used to heat the liquid. The graph in figure 8 shows the variation of the temperature of the liquid with time.

K.C.S.E Physics Q & A - MODEL 2008PP1QN16

K.C.S.E Physics Q & A - MODEL 2008PP1QN04

Water is known to boil at 1000C. A student heated some water and noticed that it boiled at 1010C.

K.C.S.E Physics Q & A - MODEL 2007PP1QN17

K.C.S.E Physics Q & A - MODEL 2006PP1QN18

K.C.S.E Physics Q & A - MODEL 2006PP1QN08

K.C.S.E Physics Q & A - MODEL 2005PP1QN20&21

K.C.S.E Physics Q & A - MODEL 2004PP2QN02

K.C.S.E Physics Q & A - MODEL 2003PP2QN06

K.C.S.E Physics Q & A - MODEL 2003PP2QN03

K.C.S.E Physics Q & A - MODEL 2003PP1QN28

A heating element rated 2.5 kW is used to raise the temperature of 3.0kg of water through 500oC. Calculate the time required to effect this. (Specific heat capacity of water is 4200 J/kgK)

K.C.S.E Physics Q & A - MODEL 2002PP2QN06

K.C.S.E Physics Q & A - MODEL 2002PP2QN04

K.C.S.E Physics Q & A - MODEL 2002PP1QN19

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FREE NOVELS

(a)
(i) Other than time, state the measurements that would be used to determine the quantity of heat P absorbed by ice in a unit time (2mks)

(ii) Complete the circuit to show the connection of the essential circuit components (2mks)

(iii) Describe how the student would proceed to determine P (3mks)

(iv) Give a reason why P may not be equal to the value indicated by the manufacturer (1mk)

(b) In another experiment, 100g of hot water at 90^oC was mixed with 20g of ice at 0^oC in a lagged plastics colorimeter. After stirring, all the ice melted and the temperature of the mixture was found to be 61.5^oC. Determine the latent heat of fusion of ice (3mks)

(i) quantity of heat lost by steam to change to water at 100 °C.
(ii) quantity of heat lost by water to cool to 0°C.
(iii) mass of ice melted at 0°C.

A student who wanted to take a bath mixed 4 kg of water at 80 ^oc with 6 kg of water at 20 ^oc.
Determine the final temperature of the water.

b) Water of mass 3.0kg initially at 20⁰C is heated in an electric kettle rated 3.0KW. The water is heated until it boils at 100⁰C. (Take specific heat capacity of water 4200Jkg1K^-1. Heat capacity of the kettle = 450JK^-1, Specific latent heat of vaporization of water = 2.3Mjkg^-1)

(d) An immersion heater rated 2.5 kW is immersed into a plastic jug containing 2 kg of water and switched on for 4 minutes. Determine;
(i) the quantity of heat gained by the water;
(ii) the temperature change for the water;
(take specific heat capacity of water as 42 x 10³Jkg^-1K^-1).

Determine:
(î) the heat absorbed by the water;
(ii) heat absorbed by the electric kettle;
(iii) the time taken for the water to boil;
(iv) how much longer it will take to boil away all the water

(a) State two factors that affect the boiling point of a liquid
(b) 100g of a liquid at a temperature of 10⁰C is poured into a well lagged calorimeter
An electric heater rated 50W is used to heat the liquid. The graph in figure 8 shows the variation of the temperature of the liquid with time.

Water is known to boil at 100⁰C. A student heated some water and noticed that it boiled at 101⁰C.

A heating element rated 2.5 kW is used to raise the temperature of 3.0kg of water through 500^oC. Calculate the time required to effect this. (Specific heat capacity of water is 4200 J/kgK)