PHYSICS FORM THREE – TOPICAL EXAMINATION

APPLICATION OF VECTORS

NAME: __________________________ 

CLASS: ______________ 

DATE: ______________

INSTRUCTIONS

1. This paper consists of Sections A and B.
2. Answer all questions.
3. Show all necessary working in calculation questions.
4. Use appropriate units in your answers.

SECTION A

1. Choose the correct answer for each of the following items.

(i) Identify the odd one out.

1. Force
2. Displacement
3. Speed
4. Velocity

(ii) The vector obtained after adding two or more vectors is called:

1. Head-to-tail vector
2. Resultant vector
3. Resultant force
4. Vector addition

(iii) Two forces of 9 N and 15 N act on an object at an angle of 60° to each other. The resultant force is approximately:

1. 15 N
2. 20 N
3. 21 N
4. 10 N

(iv) Two perpendicular forces of 8 N and 6 N act on a body. Find the magnitude of the third force that would just counter the two forces.

1. 16 N
2. 8 N
3. 10 N
4. 2 N

(v) Using the parallelogram law, find the resultant force when two forces of 20 N and 40 N act at an angle of 45° to each other.

1. 56 N
2. 10.6 N
3. 60 N
4. 20 N

(vi) Movement of an object as seen by an observer in another object is called:

1. Resultant force
2. Relative velocity
3. Relative motion
4. Constant motion

(vii) The influence of a vector in a given direction is called:

1. Combined vector
2. Coordinate vector
3. Component vector
4. Sum of vectors

(viii) Two forces of 4 N and 6 N act at an angle of 45° to each other. What is the resultant force?

1. 9.2 N
2. 4.2 N
3. 42 N
4. 0.42 N

(ix) If two vectors are represented by two sides of a triangle in sequence, the third side drawn from the tail of the first vector to the head of the second represents their resultant. This describes the:

1. Parallelogram law
2. Resultant vector
3. Triangle law
4. Relative motion

(x) The diagram below shows a block being pushed along a track. If a force of 20 N is applied in direction A at an angle of 60° to direction B, find the component of the force in direction B.

1. 10 N
2. 20 N
3. 12 N
4. 17.32 N

2. Match the items in List A with the correct responses in List B.

3. Complete each statement with the correct answer.

Note: Item (i) is missing from the original document; the remaining items are reproduced below.

(ii) When an arrow is drawn, its length represents __________ while the arrowhead shows direction.

(iii) The vector obtained after adding two or more vectors is called __________.

(iv) Adding vectors by placing the tail of the second vector at the head of the first is called __________.

(v) If vector a + vector b = c forms a triangle, the law is called __________.

(vi) Velocity of a body with respect to another is __________; motion of a body with respect to another is __________.

(vii) One application of relative motion is __________.

(viii) Lines that form a Cartesian coordinate system are called __________.

(ix) The combined influence of two components is equivalent to the influence of a __________-dimensional vector.

(x) a² + b² = c² is __________ law.

SECTION B

4. Find the resultant force F when two forces of 9 N and 15 N act on an object at an angle of 60° to each other.

5. Using the parallelogram law, find the resultant force when two forces of 20 N and 40 N act on an object at an angle of 45° to each other.

6. Two forces of magnitudes 40 N and 60 N pull a box on a horizontal table. If the angle between them is 60°, find the resultant force using the parallelogram law.

7. Explain the following terms:

1. Component of a vector
2. Resultant vector
3. Triangle law of vector addition
4. Parallelogram law of vector addition
5. Relative motion

8. A body is acted upon by two forces: F₁ = 18 N at 25° and F₂ = 30 N at 140°, measured from due east. Find the resultant force by resolving the forces into x- and y-components.

9. An aeroplane takes off at a velocity of 20 m/s. Find the components of the plane’s velocity at take-off angles of:

1. 70°
2. 45°
3. 60°

10. A river flows at a velocity of 2 m/s due south. A person in a boat wants to move across the river at 10 m/s.

1. In which direction should the person move?
2. At what velocity should the person move the boat?

END OF EXAMINATION

PHYSICS FORM THREE – TOPICAL EXAMINATION

FRICTION

Instructions: Answer all questions. Show all necessary working for calculations. Use g = 10 m/s² where required.

SECTION A

1. Choose the most correct answer for each item (i)–(x).

i. Friction means.

1. Forces that are within bodies
2. Forces that oppose relative motion
3. Molecular adhesion
4. Movement between two surfaces

ii. Friction is lowest between molecules of

1. Gases
2. Liquids
3. Solids
4. Plasma

iii. Friction in fluids is called

1. Adhesion
2. Cohesion
3. Viscosity
4. Capillarity

iv. The major cause of friction is

1. Rough surfaces
2. Moving bodies
3. Adhesive bonds
4. Molecular adhesion

v. Which statement is not true about friction?

1. Frictional force depends on the size of a body
2. Frictional force depends on the surface area of contact
3. Frictional force is independent of speed once an object is in motion
4. Frictional force depends on the nature of the surfaces in contact

vi. A scalar value describing the ratio of frictional force between two bodies to the force pressing them together is called

1. Static friction
2. Normal reaction
3. Dynamic friction
4. Coefficient of friction

vii. Dynamic friction is a type of friction in which

1. Two bodies move relative to each other
2. Two bodies do not move relative to each other
3. It depends on only one material
4. There is a net force compressing two parallel surfaces together

viii. The maximum possible value of static friction is called

1. Coefficient of limiting friction
2. Limiting friction
3. Coefficient of friction
4. Adhesive bond

ix. A box of mass 5 kg is at rest on a wooden floor. If the coefficient of static friction between the box and the floor is 0.6, what minimum external force is required to set the box sliding?

1. 3 N
2. 15 N
3. 30 N
4. 60 N

x. A block of mass 270 kg is pulled along a horizontal surface. If the coefficient of kinetic friction between the block and the surface is 0.4, what is the frictional force acting on the sliding block?

1. 270 N
2. 2700 N
3. 1080 N
4. 108.0 N

2. Match the items in List A with the correct responses from List B.

3. Fill in the blanks with the correct answers.

1. Friction that occurs when two bodies are not moving relative to each other is called __________.
2. The maximum possible value of static friction is __________.
3. Two types of frictional forces are __________ and __________.
4. Causes of friction include __________, __________ and __________.
5. Frictional force is independent of the __________ and the __________ once the body is in motion.
6. Friction that occurs when two objects move relative to each other is called __________.

SECTION B

PHYSICS FORM THREE – TOPICAL EXAMINATION

THERMAL TRANSFER OF ENERGY

SECTION A: MULTIPLE CHOICE QUESTIONS

1. Choose the most correct answer for each of the following items.

(i) Rate of transfer of energy by radiation can be increased by

1. increasing the surface temperature
2. decreasing the surface area
3. using shiny white surfaces instead of dull and black surfaces
4. decreasing the atmospheric pressure

(ii) With respect to heat transfer through conduction, which of following inequalities place solids', 'liquids' and 'gases' in right order?

1. Solids < liquids < gases
2. Solids < gases < liquids
3. Solids > gases > liquids
4. Solids > liquids > gases

(iii) Process of heat transfer that involves continual emission of infrared waves from surface of bodies and transmission of these waves without aid of medium is known as

1. Conduction
2. Convection
3. Radiation
4. None of the above

(iv) Vacuum in a vacuum flask prevents heat transfer through process of

1. Conduction only
2. Convection only
3. Conduction and Convection
4. Radiation only

(v) Which of following does not belong to list of factors that affect rate of transfer of energy by radiation?

1. Color and texture of the surface
2. Temperature of the surface
3. Movement of air above the surface
4. Surface area

(vi) Process of transfer of thermal energy by means of currents in material medium is known as

1. Conduction
2. Convection
3. Radiation
4. None of the above.

(vii) Process of transfer of thermal energy without any flow of material medium is called

1. Conduction
2. Convection
3. Radiation
4. None of the above

(viii) Soldering iron rod is made up of iron because iron is a

1. good conductor of heat
2. good insulator of heat
3. bad conductor of heat
4. good conductor of electricity

(ix) Process in which thermal energy is transferred by emission of infrared radiations is termed as

1. Conduction
2. Convection
3. Radiation
4. Conduction and Radiation

(x) Conduction in liquids and gases is less efficient than solids because

1. collision in liquids is more as compared to solids
2. collision is less as compared to solids
3. in liquids and gases, particles are in random motion
4. in liquids and gases, particles are far apart

(xi) Surface that would better absorb infrared radiations is

1. Dull and white
2. Shiny and white
3. Dull and black
4. Shiny and black

(xii) Thermal energy that reaches surface of earth from sun, is transferred through process of

1. Conduction
2. Convection
3. Radiation
4. Conduction and convection

(xiii) In vacuum, process used to transfer thermal energy is

1. Conduction
2. Convection
3. Radiation
4. Conduction and convection

(xiv) Electric kettle is a good example of

1. conduction
2. convection
3. radiation
4. conduction and radiation both

(xv) An object with a higher surface area would

1. emit and absorb more infrared radiations
2. emit more but absorb less infrared radiations
3. emit less but absorb more infrared radiations
4. emit and absorb less infrared radiations

SECTION B: STRUCTURED QUESTIONS

2. (a)

(i) What is meant by specific latent heat of vaporization.

(ii) Name two factors which affect the boiling point and freezing point of water.

(b) Explain in terms of kinetic theory of matter;

(i) What changes is taking place while the liquid is boiling?

(ii) Why it takes longer time to boil a tea on top of high mountains than at the sea level?

(c)

(i) Define heat capacity

(ii) Calculate the final temperature of water formed if 8.4 KJ of heat is supplied to 0.02 kg of ice at 0 °C.

3. (a) Define the following terms;

(i) Evaporation

(ii) Temperature.

(b) Give four differences between boiling and evaporation.

(c) An immersion heater rated 2kW is used to heat water of specific heat capacity 2200j/kgK in an insulated container of negligible heat capacity for 30minutes. Calculate the mass of water heated if the temperature of water rises from 20°C to 65°C.

4. (a) Differentiate between Heat and Temperature.

(b) Give reasons, why mercury is preferred as a best thermometric liquid?

(c)

(i) The specific heat capacity of a certain substance is what does this statement mean?

(ii) Calculate the specific heat capacity of mercury if 980J of heat is required to raise the temperature of 7g of mercury from to 1000c .

5. (a) Mention three differences between boiling and evaporation.

(b) Briefly explain reasons for the following:

(i) When a cold bottle is brought into a warm room, it becomes misted over

(ii) Frost is more likely to occur on a clear night than on a cloudy night.

(c)

(i) Define coefficient of linear expansion and give its SI unit.

(ii) A metal pipe which is 1 m long at 40°C increases in length by 0.3% when carrying a steam at 100°C. Find the coefficient of expansion of the metal.

6. (a)

(i) What is meant by specific latent heat of vaporization.

(ii) Name two factors which affect the boiling point and freezing point of water.

(b) Explain in terms of kinetic theory of matter;

(i) What changes is taking place while the liquid is boiling?

(ii) Why it takes longer time to boil a tea on top of high mountains than at the sea level?

(c)

(i) Define heat capacity.

(ii) Calculate the final temperature of water formed if 8.4 kJ of heat is supplied to 0.02 kg of ice at 0 °C.

7. a)

(i) Explain why in a very cold morning a piece of metal bar feels much colder to the hand than a piece of wood.

(ii) Clinical thermometers should not be sterilized in boiling water. Give reasons.

(b) A piece of lead of mass 500 g falls from a height of 25 m. Assuming that all the energy changes into internal energy in the lead when it strikes the ground, calculate the rise in temperature of the lead if its specific heat capacity is 130 J/kgK. (g = 10 N/kg).

8. (a) What is meant by

(i) Upper fixed point

(ii) Lower fixed point

(iii) Boiling point

(iv) Triple point of water.

(b)

(i) Give reasons, why water is not used as thermometric liquid?

(ii) Briefly explain why alcohol in glass thermometer is termed as the accuracy thermometer in arctic regions than mercury in glass thermometer.

(c) The ice and steam points on thermometer are found to be 192 apart. If the length of mercury thread is 67.2mm, calculate the temperature recorded.

(d) Explain the how heat energy in thermal flask is conserved.

PHYSICS FORM THREE – TOPICAL EXAMINATION

CURRENT ELECTRICITY

NAME: ........................................ 

CLASS: ........................

INSTRUCTIONS

1. This paper consists of Sections A and B.
2. Answer all questions.
3. Show all necessary working for calculations.
4. Use appropriate SI units in your answers.

SECTION A

1. Choose the most correct answer for each item (i)–(x).

(i) The resistance of a wire varies inversely with:

1. Area of cross-section
2. Resistivity
3. Length
4. Temperature

(ii) Voltage is a form of:

1. Kinetic energy
2. Potential energy
3. Both potential and kinetic energy
4. None of the above

(iii) Ohm’s law states which relationship between electrical quantities?

1. Voltage = current × resistance
2. Voltage = current × amperes
3. Voltage = coulombs × charge
4. Voltage = resistance × charge

(iv) Electric current is defined as the flow of:

1. Electric charge in volts per second
2. Protons in protons per second
3. Electric charge in coulombs per second
4. Electricity in electrons per second

(v) A series circuit consists of three resistors. Two resistors are 1.4 kΩ each. The total resistance is 12 kΩ. The resistance of the third resistor is:

1. 92 kΩ
2. 920 Ω
3. 9200 Ω
4. None of the above

(vi) According to Ohm’s law, if voltage increases while resistance remains constant:

1. Resistance decreases
2. Current increases
3. Current remains the same
4. Current decreases

(vii) The component used to oppose the flow of current is:

1. Capacitor
2. Resistor
3. Inductor
4. EMF

(viii) If a source of EMF is traversed from its negative terminal to its positive terminal, the potential change is:

1. Negative
2. Positive
3. Positive and negative
4. None of the above

(ix) Which instrument is used to measure resistance?

1. Ohmmeter
2. Ammeter
3. Voltmeter
4. Wattmeter

(x) A current of 3 A flows through a conductor with a potential difference of 6 V across its ends. Calculate its resistance.

1. 0 Ω
2. 0.5 Ω
3. 20 Ω
4. 12 Ω

2. Match the items in List A with the correct responses in List B.

SECTION B

3. (a) A television set rated 200 W is switched on for 5 hours every day. How much energy does it consume in 30 days?

(b) A house has five rooms, each with a 60 W, 24 V bulb. If the bulbs are switched on from 7:00 p.m. to 10:30 p.m., determine the energy consumed by the bulbs per day.

4. (a) Mention any five electrical appliances.

(b) Explain the factors affecting the quantity of heat produced by an electric current.

(c) State Joule’s law.

5. (a) Define the resistance of a conductor.

(b) A 6 Ω resistor and a 4 Ω resistor are connected in parallel. The combination is connected in series with an 8 Ω resistor. A voltmeter across the 8 Ω resistor indicates a potential difference of 3.2 V.

(i) Draw a circuit diagram to illustrate the arrangement.

(ii) Calculate the current through each resistor.

Illustrative SVG circuit diagram for Question 5(b):

(c) A water boiler is connected to a 249 V power supply. The boiler contains 150 kg of water initially at 60 °C. The resistance of its heating coil is 25 Ω.

(i) How long will it take for the water to boil?

(ii) Determine the electrical energy consumed.

6. (a) Define the following terms:

1. EMF of a cell
2. Internal resistance of a cell

(b) A cell connected in series with a 2 Ω resistor gives a current of 0.25 A. When a second 2 Ω resistor is connected in parallel with the first, the current becomes 0.3 A. Calculate:

1. The EMF of the cell
2. The internal resistance of the cell

(c) Mention three disadvantages of a Leclanché cell compared with a lead-acid accumulator.

7. (a) (i) State Ohm’s law.

(ii) State two types of electric circuits.

(b) You are given resistors of 5 Ω, 10 Ω and 20 Ω. What are the maximum and minimum resistances obtainable by connecting these resistors?

PHYSICS FORM THREE – TOPICAL EXAMINATION

LIGHT

NAME: ______________________________ 

CLASS: __________________

SECTION A

1. Choose the correct answer for each of the following questions.

(i) The midpoint between the lens surface and the principal axis is termed as:

1. Midway centre
2. Focal centre
3. Focal point
4. Optical centre

(ii) Light can travel in:

1. Air only
2. Vacuum only
3. Both air and vacuum
4. None of the media

(iii) The point at which all rays converge is termed as:

1. Converging point
2. Focal point
3. Focal centre
4. Converging centre

(iv) The distance of a virtual image and an object from a mirror is equal. This statement is:

1. Right
2. Wrong
3. May be right or wrong
4. Neither right nor wrong

(v) _________ is a form of energy.

1. Force
2. Acceleration
3. Light
4. Speed

(vi) The incident ray, reflected ray and normal lie at different points. This is:

1. A true law of reflection
2. A false law of reflection
3. A neutral law of reflection
4. A law of refraction

(vii) Two types of lenses are:

1. Small and large
2. Converging and diverging
3. Transpiring and respiring
4. Living and non-living

(viii) Objects that produce their own light are called:

1. Luminous objects
2. Non-luminous objects
3. Transparent objects
4. Opaque objects

(ix) The distance between the optical centre and the focal point is termed as:

1. Converging length
2. Focal length
3. Meeting length
4. Crossing length

(x) Total internal reflection occurs when:

1. Light passes from a denser to a lighter medium
2. Light comes into air from a vacuum
3. Light goes into a vacuum from air
4. Light passes from a denser to a less dense medium

2. Match the items in List A with the correct responses in List B.

SECTION B

3. (a) What is light?

(b) Differentiate between polychromatic light and monochromatic light.

(c) Explain how secondary colours are formed.

4. (a) Explain the image formed by a curved mirror in terms of:

1. Position
2. Nature
3. Size

(b) An object 20 cm high is placed 40 cm from a concave mirror of focal length 15 cm. Determine the position, nature and size of the image formed by drawing a ray diagram.

5. (a) An object 3 cm high is placed 30 cm away from a concave mirror of focal length 12 cm. Using the mirror formula, find the position, height and nature of the image formed.

(b) An object 30 cm high is placed 20 cm away from a convex mirror of focal length 25 cm. Describe the image formed.

6. (a) What are the uses of convex and concave mirrors?

(b) State the first and second laws of refraction.

7. (a) A coin at the bottom of a jar of glycerin appears to be 13.2 cm below the surface of the glycerin. Calculate the height of the column of glycerin in the jar, given that the refractive index of glycerin is 1.47.

(b) Give two applications of refractive index.

8. (a) What is meant by refraction of light?

(b) Mention the three points to be considered when drawing a ray diagram to form an image in a lens.

(c) Mention four effects of refraction of light.

PHYSICS FORM THREE – TOPICAL EXAMINATION

TOPIC: OPTICAL INSTRUMENTS

SECTION A

1. Choose the correct answer for each of the following items (i)–(x).

(i) A lens which converges a beam of parallel rays to a point is called:

1. Diverging lens
2. Converging lens
3. Plano-concave lens
4. Plano-convex lens

(ii) A point where incident parallel rays of light converge or appear to diverge after passing through a lens is called:

1. Centre of curvature
2. Focus
3. Optical centre
4. Aperture

(iii) The diameter of a lens is called:

1. Focal length
2. Principal axis
3. Aperture
4. Radius

(iv) When passing from an optically denser to a rarer medium, a ray of light is:

1. Undeviated
2. Bent away from the normal
3. Bent towards the normal
4. Polarized

(v) If an object is placed beyond 2F of a converging lens, the image will be:

1. Real and erect
2. Virtual and erect
3. Real and inverted
4. Virtual

(vi) The magnifying power of a microscope:

1. Increases with increasing focal length
2. Increases with decreasing focal length
3. Is unaffected by focal length
4. Equals the least distance of distinct vision

(vii) An object is 5 mm high and its image is 1 cm high. The magnification produced by the lens is:

1. 0.5
2. 0.2
3. 1
4. 2

(viii) The final image produced by a compound microscope is:

1. Real and inverted
2. Real and erect
3. Virtual and erect
4. Virtual and inverted

(ix) The critical angle is the angle of incidence in a denser medium for which the angle of refraction is:

1. 0°
2. 45°
3. 90°
4. 180°

(x) A spectrometer is used to determine:

1. Wavelength of light
2. Refractive index of a prism
3. Wavelengths of different colours
4. All of the above

2. Match the items in List A with the correct responses in List B.

SECTION B

3. (a) Define an optical instrument.

(b) Mention four types of optical instruments.

4. (a) What is a microscope?

(b) Explain how a light microscope works.

(c) Mention three uses of a compound microscope.

5. (a) What is a projection lantern?

(b) Give five uses of a projection lantern.

6. (a) A camera lens of focal length 10 cm is used to take a picture of a girl 1.5 m tall. Determine the magnification of the image if the girl is 11 m from the camera.

(b) What are the uses of a camera lens?

7. (a) Describe the structure and function of the human eye.

(b) What are the similarities between the human eye and a camera?

8. (a) Define a camera.

(b) Briefly differentiate between a camera and the human eye.

9. (a) Give the properties of an image formed by a plane mirror.

(b) Explain how a rainbow is formed.

10. (a) Explain, with ray diagrams, the use of a lens:

(i) As a magnifying glass.

(ii) In a camera.

(b) State the characteristics of the images formed in (a).