# Test for Topics Physics Form 3

TOPIC : 1  APPLICATION OF VECTORS

PHYSICS FORM THREE: TOPICAL EXAM.

APPLICATION OF VECTORS:
SECTION A:
MULTIPLE CHOICE QUESTIONS.
1. Choose the most correct answer.
(i)              Identify the odd one out
1. Force
2. Displacement.
3. Speed
4. Velocity.
(ii) The vector we get after addition of two or more vectors is called?
1. Head to tail vector
2. Resultant vector
3. Resultant force
4. Vector addition
(iii) Two forces 9N and 15N act on an object with an angle of 60 between them; the resultant force will be?
1. 15 N
2. 20 N
3. 21 N
4. 10 N
(iv) Two forces one 8 N and the other 6N are acting on a body. Given the two forces are acting perpendicular to each other, find the magnitude of the third force which 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 20N and 40N, are acting on an object with an angle of 45 between them.
1. 56N
2. 10.6N
3. 60N.
4. 20N.
(vi) Movement of an object as seen by an observer in anther object is called?
1. Resultant force
2. Relative velocity
3. Relative motion
4. Constant motion.

(vii) The influence of a vector to a given direction is called?
1. Combined vector
2. Coordinate vector
3. Component vector
4. Sum of vector

(viii) Two forces 4N and 6N are acting at an angle of 45 to one another. What is the resultant force?
1. 9.2N.
2. 4.2N.
3. 42N
4. 0.42N.

(ix) If two vectors represented by two sides of a triangle in sequence then the third closing side of triangle drawn from tail of the first vector to  head of second vector represent the resultant of the vectors in both magnitude and direction. This is?
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 20N is applied in direction A at an angle of 60 the resolved part of force in direction B will be.

1. 10N
2. 20N
3. 12N
4. 17.32N
2. Match the items from list A with those in list B.
 LIST A LIST B (i)              Has magnitude and direction (ii)            Has magnitude only. (iii)         Two vectors represented by two sides of triangle in sequence, then the third closing side of the triangle drawn from tall of the first vector to head of second vector represents the resultant of two vectors in magnitude and direction. (iv)          Movement of object as seen by an observer in another object. (v)            Velocity of a body in relative to another moving or stationery object. (vi)          Four regions formed by two axes in a plane. (vii)       Influence of a vector in a given direction. (viii)     When two vectors are added up. (ix)          Two vectors represented by two adjacent sides of parallelogram, then the diagonal of the parallelogram through the common point represent the sum of two vectors in both magnitude and direction. (x)            Adding two vectors by placing the tail of 2nd vector right at head of first vector. Graphical method Scalar Vector component Relative motion Parallelogram law Axes Resultant vector Vector component Triangle law Quadrant Vector Relative velocity Resolution Cartesian coordinate system.

3. For each of the following items (i) – (x). fill in blank spaces by writing the correct answer in your answer booklet.
(ii)                                                          When an arrow is drawn, it length represent_______ while arrow head show direction.
(iii)                                                        Vector we get after adding two or more vectors is called? ___________
(iv)                                                        Adding vectors by placing the tail of second vector right at the head of the first vector is called? _______
(v)                                                          Vector a + vector b = c, forming a triangle, this law is called?-___________
(vi)                                                        Velocity of a body with respect to another__________
Motion of a body with respect to another____________
(vii)                                                      One application of relative motion is___________
(viii)                                                   Lines which forms Cartesian coordinate system are called____________
(ix)                                                        Combined influence of two components is equivalent to the influence of a__________ dimension vector.
(x)                                                          a2 + b2 = c2 is _________________ law.

SECTION B:
4. Find the resultant force F when two forces 9N and 15N act on an object with angle of 60 between them.

5. Using parallelogram law, find resultant force when two forces 20N and 40N are acting on a object with and angle of 45 between them.

6. Two forces of magnitude 40N and 60N are pulling a box on a horizontal table. If the two forces make an angle of 60 between them, find the resultant force on box using parallelogram law.

7. Explain the following:
a)                     Component of vector
b)                     Resultant vector
c)                     Triangle aw of addition
d)                     Parallelogram law of addition
e)                     Relative motion

8. A body is being acted on by two forces. F1 = 18N action at an angle of 25 and F2 = 30N acting at 140 , from due East. Find the resultant of two forces, F, by separating the forces into x – and y – components.

9. An aeroplane is taking off at a velocity of 20mls. Find the component of the plane’s velocity if the take off angle is
a)      70 b)     45 c)      60 10. A river is flowing at a velocity of 2m/s due south. A person in a boat wants to move across the river at 10m/s/
a)      In which direction should the person move?
b)     At what velocity should the person move the boat?

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TOPIC : 2  FRICTION

PHYSICS FORM THREE: TOPICAL EXAM.
FRICTION:
SECTION A:
MULTIPLE CHOICE QUESTIONS.
1. Choose the most correct answer.
(i)              Friction means.
1.     Forces that is within bodies
2.     Forces that opposes the relative motion.
3.     Molecular adhesion
4.     Movement between two surfaces.
(ii) Friction is lowest between molecular of
1.     Gases
2.     Liquid
3.     Solid
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 surface.
2.     Moving bodies
3.     Adhesive bonds
4.     Molecular adhesion.
(v) Which is not true about friction?
1.     Friction forces is dependent of size of a body
2.     Friction forces are dependent of the surface area of contact.
3.     Friction forces are independent of speed once an object has set in motion.
4.     Friction forces depends on nature of surface is contact.
(vi) A solar value which describes the ratio of the force of friction between two bodies and surface 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 are moving relative in each other
2.     Two bodies are not moving relative to each other
3.     Depends on only one material
4.     There is a net force compressing two parallel surface 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 5kg is at rest on wooden floor. If the coefficient of static friction between the box and the flow 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 270kg is pulled along a horizontal surface. If the coefficient of kinetic friction between the block and surface is 0.4, what is the force acting on the block as it slids?
1. 270 N
2. 2700 N
3. 1080 N
4. 108.0 N

2. Match the items from list A with those in list B.
 LIST A LIST B (i)                 Forces that opposes tendency of motion between two surfaces in contact. (ii)               Ability of a liquid to flour. (iii)            Attractive force between different surfaces. (iv)             Main cause of friction between surfaces. (v)               Net force compressing two parallel forces. (vi)             Friction that occur when two surfaces are not moving relative to each other. (vii)           A scalar value that describe ration of the force of friction between two bodies and the force pressing them together. (viii)        Friction when two bodies are moving relative to each other and rub against each other. (ix)             Maximum possible value of static friction. (x)               One of reducing friction. Static friction Use of roller Smoothening surfaces Dynamic friction Normal force Limiting friction Viscosity Volatility Molecular adhesion Adhesive bonds Coefficient of friction Friction Forces Cohesive bonds

3. Fill in the gaps.
(i)              Occur when two bodies are not moving relative to each other___________
(ii)            Maximum possible value of static friction________________
(iii)         Two types of friction forces are_________ and ______________
(iv)          The causes of friction includes_________, ___________ and ___________
(v)            Friction force id independent of the _______________ and the ____________ once set in motion.
(vi)          Friction that occur when two objects are moving relative to each other is called_____

SECTION B:
4. (a) What is friction?
(b) State the laws of friction
5. (a) Outline four uses of friction in our daily life
(b) Give the advantages of friction
6. A 10 kg mass is at rest on horizontal surfaces, with no forces other than gravity and normal force acting on it.
(a) Given that the coefficient of static and kinetic friction between the surface and the mass are 0.5 and 02 respectively.
(i) What is the force of static friction between the object and surface?
(ii) What minimum horizontal force is required to start object sliding?
7. A 6kg mass is resting on a horizontal surface. It is determined that a force of 20N will start the object sliding and keep it sliding with an acceleration of 0.83mls2. What are the coefficient of static and kinetic frictions between the mass and the surface?
8. A box of mass 5kg is at rest on a wooden floor. The coefficient of static friction is 0.42 and coefficient of kinetic friction is 0.15. Find its acceleration if a force of:
(a) 15 N is applied to the box.
(b) 25 N is applied to the box.
9. (a) Explain why most vehicles have their engines directly over the wheels?
(b) Explain four methods of reducing friction.
10. A rectangular box of mass 10kg rests on an incline with a coefficient of static friction of 0.55 and a coefficient of kinetic friction of 0.25.
(a) At what angle with the box begin to slide.
(b) If the incline is kept at an angle after the box begins to slide, what will be the box acceleration?
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TOPIC : 4  TRANSFER AND MEASUREMENT OF THERMAL ENERGY

TOPICAL EXAMINATIONS
THERMAL TRANSFER OF ENERGY FORM THREE
SECTION A
1. 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
2. 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
3. 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
4. Vacuum in a vacuum flask prevents heat transfer through process of
1. Conduction only
2. Convection only
3. Conduction and Convection
4. Radiation only
5. 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
6. 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.
7. 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
8. 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
9. 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
10. 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
11. Surface that would better absorb infrared radiations is
1. Dull and white
2. Shiny and white
3. Dull and black
4. Shiny and black
12. Thermal energy that reaches surface of earth from sun, is transferred through process of
1. Conduction
2. Convection
3. Radiation
4. Conduction and convection
13. In vacuum, process used to transfer thermal energy is
1. Conduction
2. Convection
3. Radiation
4. Conduction and convection
14. Electric kettle is a good example of
1. conduction
2. convection
3. radiation
4. conduction and radiation both
15. 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
1. (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.
1.         (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.
1.                   (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       .
1. (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.
1.      (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.
1.      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).
1.         (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.

TOPIC : 5  CURRENT ELECTRICITY

TOPICAL EXAMINATIONS
CURRENT ELECTRICITY
SECTION A

1. Multiple choice questions.

(i) The resistance of a wire varies inversely to:
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.               Volts = current resistance
2.                Volts = current amps
3.                Volts = coulomb charge
4.               Volts = resistance charge
(iv) Electric current is defined as flow of:-
1.               Electric charge in units of volts per sec.
2.                Protons in units of protons per second
3.                Electric charge in units of coulomb per second
4.               Electric in units of electrons per second.
(v) A series of circuit consists of three resistors. Two resistors are 1.4k each. The total resistance is 12k. The value of third resistor is
1.               92K Ohm
2.                920 Ohm
3.                9200 Ohm
4.               None of the above.
(vi) According to Ohm’s Law, If voltage increases and resistance stays the same
1.               Resistance decreases
2.                Current increases
3.                Current remains the same
4.               Current decreases.
(vii) The name of component used to oppose flow current is
1.               Capacity
2.                Resistors
3.                Inductor
4.               EMF.
(viii) If a source of EMF is transverse from negative to positive terminal the potential charge is
1.               Negative
2.                Positive
3.                Positive and Negative
4.               None of above
(ix) Which of these test equipment is used to measure resistors?
1.               Ohmeter
2.                Ammeter
3.                Voltmeter
4.               Wattmeter
(x) A current of 3A flows through a conductor whose ends are at p.d of 6v. Calculate resistance of Conductor.
1.               0 Ohm
2.                0.5 Ohm
3.                20 Ohm
4.               12 Ohm

2. Match the following items.

 List A List B (i)                Ability to oppose flow of current (ii)              Path around which electrons can flow (iii)            Wire with high potential difference relative to other wires in a cable (iv)            Wire dipped into ground near home to protect appliances (v)              Work done by moving unit of electricity from one point to another Current electricity                Volt                Potential difference               Live wire                Earth wire                Coulombs                Electric circuit               Ammeter                  Resistivity

SECTION B
3. (a) A television se rated 200W 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 60W, 24V bulb. If the bulb is switched on 7:00 p.m. to 10:30 p.m. determine power consumed by bulbs per day.

4. (a) Mention any five electrical appliances
(b) Explain factors affecting heat quantity of a current
(c) State Joule’s Law.

5. (a) Define the term resistance of a conductor.
(b) A 6Ώ and 4Ώ resistors are combined in parallel and the combination is connected in series with an 8Ώ resistor. When the whole system is connected to a certain power supply the potential difference of 3.2v is indicated by voltmeter across the 8Ώ resistor.
(i)                Draw a circuit diagram to illustrate above problem.
(ii)              Calculate the current of each resistor.
(c) Water boiler is connected to the 249v power supply. The boiler contains 150kg of water initially at a temperature of 60 . If the resistance of heating of coil initially is 25Ώ
(i)                How long will it take for water to boil?
(ii)              Determine electrical energy consumed.

6. (a) Define the terms
(i)                E.M.F of a cell
(ii)              Internal resistance of a cell
(b) A cell connected in series with a 2Ώ resistor gives a current of 0.25A. When a second 2Ώ resistor is connected parallel with the first one the current becomes 0.3A. Calculate
(i)                E.M.F of a cell
(ii)              Internal resistance of a cell.
(c) Mention three disadvantage of a le – clariche cell over lead acid accumulator.

7. (a) (i) State Ohms Law
(ii) State two types of electric circuit
(b) You have been given resistors of 5Ώ, 10Ώ and 20Ώ. What are the maximum and minimum resistances obtained by connecting those resistors?

TOPIC : 6  LIGHT

TOPICAL EXAMINATION
LIGHT
SECTION A

1. Multiple choice questions.
(i) Midpoint between lens surface and principle axis is termed as:-
1.               Mid way center
2.                Focal center
3.                Focal point
4.               Optical center.
(ii) Light can travel in
1.               Air only
2.                Vacuum only
3.                Both air and vacuum
4.               None of the mediums
(iii) Point at which all rays converge in termed as
1.               Converging point
2.                Focal point
3.                Focal center
4.               Converging center
(iv) Distance of virtual image and object is equal from mirror. 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) Incident ray, reflected ray and normal ray lie at different points is a
1.               True law of reflection
2.                False law of reflection
3.                Neutral law of reflection
4.               It’s 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) Distance between optical center and 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 through a denser to a lighter medium
2.                Light comes into air from vacuum
3.                Light goes to vacuum from air
4.               Light passes from denser to less dense medium

2. Match the following items

 List A List B (i)                Image on opposite side of mirror (ii)              Ratio of angle of incidence to angle of refraction (iii)            Unique angle incidence for which angle of refraction is 90 . (iv)            Distance between optical center and principle focus (v)              Angle formed by intersection of incident ray direction and emergent ray direction Principle focus                Refractive index                Absolute index.               Focal length                Angle of deviation                Real image                Virtual image               Snell’s law

SECTION B
3. (a) What is light?
(b) Differentiate polychromatic light and monochromatic light
(c) Explain how secondary colours are formed?

4. (a) Explain the image formed by curved mirror in terms of:-
(i)                Position
(ii)              Nature
(iii)            Size
(b) An object 20cm high is placed 40cm from a concave mirror of focal length 15cm. Determine position, nature and size of image formed by drawing a ray diagram.

5. (a) An object 3cm high is placed 30cm away from concave mirror of focal length 12cm. Using the mirror formula, find the position, the height and the nature of image formed.
(b) An object 30cm high placed 20cm away from a convex mirror focal length 25cm. Describe image formed.

6. (a) What are uses of convex and concave mirrors
(b) State first and second law of refraction.

7. (a) A coin at the bottom of a jar of glycerin appears to be 13.2cm below the surface of glycerin. Calculate the height of the column of glycerin in jar given that 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 the image in lens.
(c) Mention four effects of refraction of light.

TOPIC : 7  OPTICAL INSTRUMENTS

TOPICAL EXAMINATION
OPTICAL INSTRUMENTS
SECTION A

1. Multiple choice questions

(i) A lens which converge a beam of parallel rays to a point is called?
1.              Diverging lens
2.               Converging lens
3.               Plane concave lens
4.              Plane convex lens
(ii) A point where the incident parallel rays of light converge or appear to diverge after passing through a lens is called?
1.              Center of curvature
2.               Focus
3.               Optical center
4.              Aperture.
(iii) The diameter of a lens is called?
1.              Focal length
2.               Principal axis
3.               Aperture
4.              Radius
(iv) In going from a denser to rarer medium a ray of light is?
1.              Undervialed
2.               Bent away from the normal
3.               Bent towards the normal
4.              Polarized.
(v) If an object is placed away from 2f of a converging lens then the image will be;
1.              Real and erect
2.               Virtual and erect
3.               Real and inverted
4.              Virtual
(vi) Magnifying power of microscope
1.              Image with increase of focal length
2.               Increase with decrease of focal length
3.               No effect with decrease or increase with focal length
4.              List distance of distinct vision
(vii) Image of an object 5mm high is only 1cm high. Magnification produced by lens is?
1.              0.5
2.               0.2
3.               1
4.              2
(viii) 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) Critical angle is that incident angle in denser medium for which angle of refraction is?
1.              0 2.               45 3.               90 4.              180 (x) A spectrometer is used to find?
1.              Wave length of light
2.               Refractive index of the prism
3.               Wavelength of different colors
4.              All of the above.

2. Match the following items
 List A List B (i)                 Control length entering lens in a film (ii)               Short – sightedness (iii)            Long sightedness (iv)             Bringing a near or far object into focus (v)               Small object is made to appear big. Optical instrument               Hypermetropia               Accommodation              Shutter               Magnification                Myopid              Angular magnification              Aperture

SECTION B
3. (a) Define optical instrument
(b) Mention four types of optical instruments

4. (a) What is a microscope?
(b)Explain how light microscope works
(c) Mention three uses of compound microscope

5. (a) What is a projection lantern
(b) Give five uses of a projectile lantern.

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

(b) What are used of lens of a camera?

7. (a) Describe structure and function of human eye.
(b) What are similarities between human eye and camera?

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

9. (a) Give properties of image formed by plane mirror
(b) Explain how rainbow is formed.

10. (a) Explain with a ray diagram, the use of lens as
(i)                 As a magnifying glass
(ii)               In a camera
(b) State the characteristics of image formed above.