REVISION QUESTIONS - 1

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FORM ONE WORK

INTRODUCTION TO PHYSICS

PAST KCSE QUESTIONS ON THE TOPIC

1. State two factors that should be controlled in manufacturing a cylindrical container of uniform thickness, which should normally be in a standing position.
2. The figure shows a measuring cylinder which contains water initially at level A. A solid mass 11g is immersed in the water, the level rises to B.

Determine the density of the solid. (Give your answer to 1 decimal point)

3.        A butcher has a beam balance and masses 0.5 kg and 2 kg. How would he measure 1.5 kg of meat on the balance at once.
4. The number of molecules in 18cm³ of a liquid is 6 x 10²³. Assuming that

the diameter of the molecules is equivalent to the side of a cube having the same length as the molecule. Determine the diameter of the molecule.

4. Determine the density in kg/m³ of a solid whose mass is 40g and whose dimensions in cm are 30 x 4 x 3
5. Record as accurately as possible the masses indicated by the pointer in figures A.

6.             Figure 1 shows the reading on a burette after 55 drops of a liquid have

been used.

If the initial reading was at 0cm mark, determine the volume of one drop.

                                                                                                      (2 marks)

7. Fig. 1 shows the change in volume of water in a measuring cylinder when an irregular solid is immersed in it.

Given that the mass of the solid is 567g, determine the density of the solid in gcm^-3. (Give your answer correct to 2 decimal places.

8. A thin wire was wound 30 times closely over a boiling tube.   The total length of the windings was found to be 9.3 mm.   Calculate the radius of the wire.
9. (a)        Given that a kilogram of copper contains about 10²⁵ atoms and that density

of copper is about 9000kg/m³_/ estimate the diameter of the copper atom?

      (b)       State the assumption made in (9a) above.

10. A drop of oil of volume 1.0 x 10^-3 spreads out on clean water surface to a film of area 10cm². Calculate the thickness of the film.
11. A small drop of oil has a volume of 5 x 10^-8m³. When it is put on the surface of some clean water, it forms a circular film of 0.lm² in area;

(i)        What is the size of a molecule of oil?

(ii)       State two assumptions you make in your calculations?

12. The density of concentrated Sulphuric acid is 1.8gcm^-3. Calculate the volume of 3.6kg of the acid.
13. 1600 cm³ of fresh water of density l g/cm³ are mixed with 1400cm³ of seawater of density 1.25g/cm³. Determine the density of the mixture.

TOPIC 2

FORCES

PAST KCSE QUESTIONS ON THE TOPIC

1. A student was heard saying “the mass of a ball on the moon is one sixth its

mass on earth”. Give a reason why this statement is wrong.

2. In the study of a free fall, it is assumed that the force f  acting on a given

body of mass m is gravitational, given by F= mg. State two other forces that act on the same body.

3. State how a lubricant reduces friction in the bearings of moving part of a

machine.

4. Distinguish between mass and weight of a body stating the units for each.
5. State with reason the purpose of the oil that circulates in a motorcar

engine.

6. Name two types of forces which can act between objects without contact.
7. A house in which a cylinder containing cooking gas is kept unfortunately

catches fire. The cylinder explodes. Give a reason for the explosion.

8. Give a reason why the weight of a body varies from place to place
9. State why a pin floating on water sinks when a detergent is added.
10. The figure below represents a rock balanced at point O.  G is the center of gravity of the rock. Use this information to answer the following questions:
    
    
    
    
    
    (a)   Draw and label on the figure the forces acting on the rock
    (b)   If the portion of the rock represented by the shaded part is chopped off, explain why the rock may topple to the right.
    11. The figure shows a non- uniform log of mass 100kg balanced on a pivot
    by a 2 kg mass placed as shown.
    
    
    
    
    
    
    

                  Determine the distance of the centre of gravity of the log from the pivot

12. The figure below show two identical trolleys with loads A and B. The

loads are identical in shape and size.

Given that the density of A is greater than that of B, explain why the trolley in figure 3 (ii) is more stable.

13.  Fig 2 shows a beaker placed on a bench. A block of ice is placed in thebeaker as shown. State and explain the change in the stability of the beaker when the ice melts.

14. The system in figure 9 is in equilibrium

                  Determine the weight of the bar.                                            (3 marks)

15. (a) Give a reason why water is not a suitable liquid for use in a barometer

(b) Fig. 3 is a simplified diagram of a hydraulic jack. The cross selection

area A2 of the load piston is 25 times the A1 of the effort piston, A2 = 25N. F1 is the force applied (Effort) while F₂ represents A1 the load.

                        (i)        Write an expression for the pressure exerted on the liquid by the

effort piston.                                                               (1 mark)

A mechanic applies a force of 100N on the effort piston while raising the rear part of a car.

(ii)       Determine the maximum load that can be raised       (2 marks)

(iii)      Give a reason why gas is not suitable for use in place of the liquid

in the jack                                                                    (1 mark)

16. 2005:   Fig 2 shows a solid cylinder standing on a horizontal surface. The cylinder

is in stable equilibrium

On the horizontal space provided, sketch the cylinder in neutral equilibrium.                                                                                  (1 mark)

17. Fig 8 shows water drops on two surfaces. In 8 (a), the glass surface is

smeared with wax while in 8 (b) the glass surface is clean.

                  Explain the difference in the shapes of the drops.                  (2 marks)

18. A see – saw of length 5 m is pivoted at the centre. A student of mass 50kg sits at one end and is balanced by another student of mass ‘m’ sitting at a distance of 1m from the other end. Calculate the value of ‘m’
19. An astronaut is on the moon. He drops a hammer from a height of 3.2m and it takes 2.0s to hit the lunar landscape. What is the acceleration due to gravity of the moon?
20. An unloaded spring has a length of 15cm and when under a load of 24N it has a length of 12cm.  What will be the load on the spring when length is 10cm?
21. Two copper spheres M and N are joined by a light rod such that their center of mass are 30cm apart: if the radius of M is 2 times the radius of N, find the position of the COG from mass M.
22. In the diagram below the system is in equilibrium. Determine the value of F₁ in N.

23. Fig 3 shows a device for closing a steam outlet. The area of the piston is 4.0 x 10^-4m² and the pressure of the steam in the boiler is 2.0 x 10⁵Nm². Determine the weight W that will just hold the bar in the horizontal position shown.

24. The total weight of a car with passengers is 25,000N. The area of contact of each of the four tyres with the ground is 0.025m². Determine the minimum car tyre pressure.
25. A drum which is 2m high contains water to a depth of 0.5 m and oil of density 0.5g/cm³ extends to the top. Find the pressure exerted at the bottom of drum by the two liquids.
26. Figure 2 shows a non- uniform rod, lying in a horizontal position. Vertical force of 5N and 4 N can just lift the rod when applied at the end A and B respectively.

If the rod is 1.8m long find

(i)        The position of the centre of gravity

(ii)       The weight of the rod

TOPIC 3

PRESSURE

PAST KCSE QUESTIONS ON THE TOPIC

1. Give a reason why a concrete beam reinforced with steel does not crack

when subjected to changes in temperature.

2. The figure below shows part of a set up used by a student to demonstrate

the expansion of a wire.

(i)                 What three other items, not shown in the fig would be needed in order to perform the experiment

(ii)              What purpose does the stone serve?

3. 2001:   State the reason why it may not be possible to suck liquid into your mouth

using a drinking straw on the surface of the moon.

Figure 3 shows the levels of two liquids A and B after some air has been sucked out of the tubes through the tap. Use this information and the figure to answer questions 4 and 5.

4. The total weight of a car with passengers is 25000N. The area of contact

of each of the FOUR tyres with the ground is 0.025m²

Determine the minimum car tyre pressure.

(a)   Write an expression for pressure on a liquid in hydraulic jack

(b)   While using a jack, a mechanic applied a force of 100N on the effort piston while raising the rear part of a car.

-          Determine the maximum load that can be raised

-          Give a reason why gas is not suitable for use in place of the liquid in a jack.

5. State the mode by which heat travels from the cube to the balloons.

(1 mark)

6. The face of the cube towards A is bright and shiny and the face

towards B is dull- black. State with reason the adjustments that should be made on the distances X₁ and X₂ so that the rate of change of temperature in both balloons is the same.   (1 mark)

7. Explain why the pressure of a gas increases when the mass of the gas in the container is increased.
8. The lift pump is effective for pumping water as long as the well is less than 10m deep. Explain.
9. The reading on a mercury barometer at Mombasa is 760mm. Calculate the pressure at Mombasa (density of mercury = 1.36 x 10⁴ Kgm^-3)
10. State one property of a barometer liquid and explain its effects.

TOPIC 4

THE PARTICULATE NATURE OF MATTER.

PAST KCSE QUESTIONS ON THE QUESTIONS

1. State the reason for the rise in the levels of the liquids when air is

sucked from the tubes                                                 (1 mark)

2. Given that the density of liquid B is 1200 kgm³, determine the

density of liquid A.                                                     (3 marks)

3. Brownian motion of smoke particles can be studied by using the apparatus shown in figure 9. To observe the motion, some smoke is enclosed in the smoke cell and then observed through the microscope
 

 

(a)   Explain the role of the smoke particles, lens and microscope in the experiment.                                                                              (6 marks)

(b)   State and explain the nature of the observed motion of the smoke particles.                                                                                                             (3 marks)

(c)   State what will be observed about the motion of the smoke particles if the temperature surrounding the smoke cell is raised slightly.   (1 mark)

TOPIC 5

THERMAL EXPANSION

PAST KCSE QUESTIONS ON THE TOPIC

1. The figure below shows an arrangement for a solar water purifier for dirty. 

(i)                 Describe how the solar water purifier works

(ii)              Explain the role of:

(a)   Black coating

(b)   The pieces of charcoal in the tray

(iii)            State why the solar water purifier continues to work when sun rays are cut off.

(iv)             Explain the green house effect process in the purifier above.

2.        The figures (a) and (b) show a convex mirror and a plane mirror of equal
   aperture.

By sketching a pair of incident and reflected rays for each (a) and (b) show how the convex mirror provides to the eye, a wider field of view than the plane mirror.

3. 2004:   Figure 12 shows a parabolic surface with a source of light placed at its focal point F.

Draw rays to show reflection from the surface when rays from the source strike the surface at points ABC and D.

4. 2005:   Fig 12 shows a vertical object O, placed in front of a convex mirror.

                  On the same diagram draw the appropriate rays and locate the image

formed.                                                                                   ( 3 marks)

5. Figure 1 represents a pinhole camera. Sketch rays to show the

formation of an enlarged image in the camera. Label both the objects and the image.

6. Figure 3 shows an object, O in front of a concave mirror and its

image, 1 formed after reflection.

(a)   On the same diagram appropriate ray(s) to locate the principal focus ‘F’ of the  mirror                                                       (2 marks)

(b)   Determine the focal length  of the mirror (scale 1:5)       (1 mark)

7. Liquids expand more than solids. Explain why

TOPIC 6

HEAT TRANSFER

PAST KCSE QUESTIONS ON THE TOPIC

1. An electric heater is placed at equal distances from two similar cans A and

B filled with water at room temperature. The outer surface of can A is shiny while that of can B is dull black. State with reasons, which of the cans will be at higher temperature after the heater is switched on for some time.

2. In the set up shown in figure 4, it is observed that the level of the water

initially drops before starting to rise.

                  Explain this observation.

3. When a Bunsen Burner is lit below a wire gauze, it is noted that the flame

initially burns below the gauze as shown in figure (i),  after sometime, the flame burns below as well as above the gauze as shown in figure (ii)

                  Explain this observation

4. In a vacuum flask the walls enclosing the vacuum are silvered on the

inside. State the reason for this                                               (1 mark)

Figure 4 shows two identical balloons A and B. The balloons were filled with equal amounts of the same type of gas. The balloons are suspended at distances X₁ and X₂ from a metal cube filled with boiling water and placed on an insulating material. Use this information to answers questions 5 and 6.

5. State the mode by which heat travels from the cube to the balloons

(1 mark)

6. The face of the cube towards A is bright and shiny and the face

towards B is dull black. State with reason the adjustments that should be made on the distances X₁ and X₂ so that the rate of change of temperature in both balloons is the same.   (1 mark)

7. Temperature scale in clinical thermometer ranges from 35⁰c to 43⁰c. Explain.
8. State one application of expansion in gases
9. Why is it that boiling is not used for sterilization of clinical thermometer?
10. Describe ONE advantage and ONE Disadvantage of anomalous behavior of water.
11. (a) Draw a well labeled diagram of a vacuum flask

(b) Stating the specific parts in the flask explain how heat loss is reduced through:

(i)        Conduction

(ii)        Convection

(iii)      Radiation

12. In the diagram below the ice remains in solid state for several minutes as heating continues. Explain the phenomenon.

TOPIC 7

RECTILINEAR PROPAGATION OF LIGHT AND REFLECTION AT PLANE SURFACES

PAST KCSE QUESTIONS ON THE TOPIC

1. What is meant by a virtual image?
2. The figure below shows an object O being viewed using two inclined

mirrors M1 and M2.

Complete the diagram by sketching rays to show the position of the image as seen by the eye E

3. The figure below shows an object O placed in front of a plane mirror

On the same diagram, draw rays to locate the position of the image 1 as seen from the eye E.

4. The diagram shows a ray of light incident on a plane mirror at point O.

The mirror is rotated clockwise through an angle of 30⁰ about an axis perpendicular to the paper. Determine the angle through which the reflected ray rotated.

5. A luminous point object took 3 s to move from P to Q in front of a pinhole camera as shown below.

What is speed in cm/s of the image on the screen?

6. The diagram shows the image of a watch face in a plane mirror

      What is the time shown on the watch face?

7. (a) Give two main reasons why concave mirrors are unsuitable as driving mirrors

(b) State one disadvantage of a convex mirror as a driving mirror

8. Explain why a concave mirror is suitable for use as a make up mirror.
9. In the space provided below, sketch a labeled diagram to show how a pinhole camera forms an image of a vertical object placed in front of the pinhole      

(3 marks)

10. A building standing 100m from a pinhole camera produces on the screen of the camera an image 5 cm high 10 cm behind the pinhole. Determine the actual height of the building.                                                                                   ( 3 marks)

TOPIC 8

ELECTROSTATICS 1

PAST KCSE QUESTIONS ON THE TOPIC

1. Two isolated and insulated spheres A and B carry the same positive

charge. Sketch the electric lines of force of their field when placed close to each other but not touching some.

2. State the observation on the leaves of a positively charged electroscope

when a negative charge is brought near it.

3. The fig shows sketches of two types of houses built in a lighting prone

area. State with reason which house is safer to stay in during lighting and thunderstorms?

4. The diagram below shows a circuit with a capacitor C and a lamp L.  When the sketch is closed at Y, the lamp L lights. When the switch is closed at X, L does not light. Explain the observation.

5. In the clothing and textile industries the machines experiences

electrostatics forces at certain points. Suggests one method of reducing these forces.

6. State two other factors to be considered in constructing a capacitor other

than the surface area of the plates.

7. State the precaution that is taken when charging a metal object.
8. (a)        (i)         State coulombs law of electrostatic force

(ii)        Define capacitance

(b)       Describe how the type of charge on a charged metal rod can be

determined

(c)        The fig. Shows hollow negatively charged sphere with a metal disk attached to an insulator placed inside. State what would happen to the leaf of an uncharged electroscope if the metal disk were brought near the cap of the electroscope. Give a reason for your answer.

(d)       State two ways of charging the magnitude of the deflection of the leaf of an electroscope.

(e)        The fig- shows an arrangement of capacitors connected to a 10V d.c supply. Determine:

(i)        The charge stored in the 2μ F capacitor.

(ii)       The total capacitance of the arrangement.

9. Explain why the leaf of an uncharged object is brought near the cap.
10. A glass rod can be charged positively by rubbing it with silk. Explain what happens when the glass rod is being charged.

TOPIC 9

CELLS AND SIMPLE CIRCUITS

PAST KCSE QUESTIONS ON THE TOPIC

1. A student learnt that a battery of eight dry cells each 1.5V has a total e.m.f

of 12V the same as a car battery. He connected in series eight new dry batteries to his car but found that they could not start the engine.

Give a reason for this observation

2. Distinguish between a primary cell and a secondary cell.
3. What current will a 500Ω resistor connected to a source of 240V draw?
4. A current of 0.08A passes in a circuit for 2.5 minutes. How much charge

passes through a point in the circuit?

5. In large circuits, large resistors in parallel are preferred to low resistors in

series. Explain.

6. State two advantages of an alkaline battery over a lead acid battery.
7. A current of 0.5A flows in a circuit. Determine the quantity of charge that

crosses a point in 4 minutes.

8. Explain why the bulb in figure 10 (b) will be brighter than each of the

bulbs in figure 10 (a).                                                              (2 marks)

9. Give the reason why the cells in figure 10 (b) Can be used for a longer

period than the cells in Fig 10 (a)

10. State the purpose of manganese dioxide in a dry cell.            (1 mark)

11. A student wishes to investigate the relationship between current and

voltage for a certain device X. In the space provided, draw a circuit diagram including two cells, rheostat, ammeter, voltmeter and the device X that would be suitable in obtaining the desired results.            (1 mark)

12. State one advantage of an alkaline cell over a lead acid cell

(1 mark)

13.  In the circuit diagram  shown in figure 7, the ammeter has

negligible resistance. When the switch S is closed, the ammeter reads 0.13A.                                                                     (3 marks)

(a)   State Ohm’s law

(b)   The graph in figure 9 shows the  current voltage characteristics of a device, X

(i) State with a reason whether the device obeys Ohm’s laws    (2 marks)

(ii) Determine the resistance of the device X when the current through it is

60mA.

(iii)             When the device X is connected in the circuit below, the voltage across it

is 0.70V.

Calculate the value of the resistance R.

(c) The cell in figure 10 has an emf of 2.1V and negligible internal resistance.

Determine the

(i)        Total resistance in the circuit                                      (2 marks)

(ii)       Current in the circuit                                                   (1 mark)

(iii)      Reading on the voltmeter                                            (2 marks)

14. Explain clearly the precautionary measures you would take to maintain the efficiency of an accumulator?
15. State the advantage of Nickel-cadmium battery over the lead -acid type
16. Draw a well labeled diagram of a dry cell
17. When ammeter is connected between the two plates of a simple cell, the pointer deflects along the scale. Explain

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