Free KCSE Physics Topical Questions KNEC Standards

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

29/7/2020

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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FORM I - PHYSICS SYLLABUS

Introduction to Physics (4 Lessons)
Measurements 1 (12 Lessons)
Force (16 Lessons)
Pressure (24 Lessons)
Particulate Nature of Matter (12 Lessons)
Thermal Expansion (12 Lessons)
Heat Transfer
Rectilinear Propagation of Light and Reflection at Plane Surface (16 Lessons)
Electrostatics (12 Lessons)
Cells and Simple Circuits (12 Lessons)

FORM II - PHYSICS SYLLABUS

Magnetism (12 Lessons)
Measurements II (16 Lessons)
Turning Effect of Force (10 Lessons)
Equilibrium Centre of Gravity (12 Lessons)
Reflection at Curved Surfaces (16 Lessons)
Magnetic Effect of Electric Current (18 Lessons)
Hooke's Law (8 Lessons)
Waves (14 Lessons)
Sound (12 Lessons)
Fluid Flow (14 Lessons)

FORM III - PHYSICS SYLLABUS

Linear Motion (20 Lessons)
Refraction of Light (20 Lessons)
Laws of Motion (15 Lessons)
Energy, Power and Machines (20 Lessons)
Current Electricity (20 Lessons)
Waves II(10 Lessons)
Electrostatics II (15 Lessons)
Heating Effect of Electric Current (10 Lessons)
Quantity of Heat (20 Lessons)
Gas Laws (15 Lessons)

FORM IV - PHYSICS SYLLABUS

Thin Lenses (20 Lessons)
Uniform Circular Motion (10 Lessons)
Floating and Sinking (15 Lessons)
Electromagnetic Spectrum (15 Lessons)
Electromagnetic Induction (20 Lessons)
Mains Electricity (10 Lessons)
Cathode Rays and Cathode Ray Tube (10 Lessons)
X-rays (8 Lessons)
Photoelectric Effect (15 Lessons)
Radioactivity (15 Lessons)
Electronics (10 Lessons)

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

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

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

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 2015PP1QN16

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

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

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

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

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

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 2015PP1QN16

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

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

Categories

FORM I - PHYSICS SYLLABUS

FORM II - PHYSICS SYLLABUS

FORM III - PHYSICS SYLLABUS

FORM IV - PHYSICS SYLLABUS

Archives

M.A Nyamoti

HIGH SCHOOL RESOURCES

PRIMARY SCHOOL RESOURCES 8-4-4

PRIMARY SCHOOL RESOURCES CBC

COLLEGE RESOURCES

FREE NOVELS

Send Us a Message

(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)