Free KCSE Physics Topical Questions KNEC Standards

K.C.S.E Physics Q & A - MODEL 2009PP2QN19

17/7/2020

K.C.S.E Physics Q & A - MODEL 2009PP2QN19

Figure 12 shows a set up for observing interference of waves from two sources S1 and S2. The points C and D represent positions of the constructive and destructive interference respectively as observed on the screen

(a) If the observation was made in a ripple tank, describe:
(i) How the constructive and destructive interferences are identified
(b) Explain how the constructive interference C and the destructive interference D patterns are produced.
Draw:
(i) The line joining all points where waves from S1 and S2 have traveled equal distance. Label it A
(ii) The line joining all points where waves from S2 have traveled one wavelength further than the waves from S1. Label it B.

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K.C.S.E Physics Q & A - MODEL 2009PP2QN18

17/7/2020

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K.C.S.E Physics Q & A - MODEL 2009PP2QN18

(a) It is observed that when ultra- violet radiation is directed onto a clean zinc plate connected to the cap of a negatively charged leaf electroscope, the leaf falls
(i) Explain this observation
(ii) State why this observation does not occur if the electroscope is positively Charged
(iii) Explain why the leaf of the electroscope does not fall when infra- red radiation is directed onto the zinc plate

(b) State the effect on the electrons emitted by the photoelectric effect when:
(i) The intensity of incident radiation is increased
(ii) The frequency of the incident radiation is increased
(c) The maximum wavelength required to cause photoelectric emission on a metal surfaces is 8.0 x 10^-7m. The metal surface is irradiated with light of frequency 8.5 x 10¹⁴ Hz.
Determine:
(i) The threshold frequency
(ii) The work function of the metal in electron volts
(iii) The maximum kinetic energy of the electrons
Take: leV= 1.6 x 10^-19J.
Speed of light = 3.0 x 108 ms^-1
Plank's constant, h = 6.63 x 10^-34 Js

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K.C.S.E Physics Q & A - MODEL 2009PP2QN17

17/7/2020

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K.C.S.E Physics Q & A - MODEL 2009PP2QN17

(a) Figure 11 shows the path of radiation from a radioactive source. The field is perpendicular to the paper and directed out of the paper.

Identify the radiation
(b) Radiation from a radioactive source enters a G.M tube
(i) State the effect of the radiation on the gas inside the tube
(ii) Explain hoe the large discharge current is created
(c) The following is a nuclear equation for a fission process resulting from the reaction of a neutron with a Uranium nucleus

(i) Determine the values of x and y
(ii) State the source of the energy released
(iii) Explain how this reaction is made continuous in a nuclear reactor

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K.C.S.E Physics Q & A - MODEL 2009PP2QN16

17/7/2020

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K.C.S.E Physics Q & A - MODEL 2009PP2QN16

(a) Figure 10 shows a ray of light incident on a triangular glass prism and white screen S placed after the prism

(i) Complete the path of the ray through the prism to show how a spectrum is formed on the screen
(ii) A thermometer with a blackened bulb is placed at various parts of the spectrum. State with reason the region where the thermometer indicates the highest reading
(b) A pin is placed at the bottom of a beaker of depth 11.5 cm. The beaker is then filled with kerosene. By using another on the side of the beaker and observing from the top, the distance of the image of the pin in the beaker is found to be 3.5 cm from the bottom. Determine the refractive index of kerosene.

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K.C.S.E Physics Q & A - MODEL 2009PP2QN15

17/7/2020

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K.C.S.E Physics Q & A - MODEL 2009PP2QN15

Figure 9 shows the graph of the relationship between current I and potential difference V for two trungsten filament lamps X and Y. The normal working voltages for the lamp X and lamp Y are 2.5V and 3.0V respectively.

(b) Determine the resistance of lamp X at the normal working voltage
(c) The lamps are now connected in a series circuit in which a current of 0.4 A flows. Find the potential differences across lamp Y
(d) Determine the power at which lamp Y operates under normal working voltage

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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 2009PP2QN19

K.C.S.E Physics Q & A - MODEL 2009PP2QN19

K.C.S.E Physics Q & A - MODEL 2009PP2QN18

K.C.S.E Physics Q & A - MODEL 2009PP2QN18

K.C.S.E Physics Q & A - MODEL 2009PP2QN17

K.C.S.E Physics Q & A - MODEL 2009PP2QN17

K.C.S.E Physics Q & A - MODEL 2009PP2QN16

K.C.S.E Physics Q & A - MODEL 2009PP2QN16

K.C.S.E Physics Q & A - MODEL 2009PP2QN15

K.C.S.E Physics Q & A - MODEL 2009PP2QN15

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FORM I - PHYSICS SYLLABUS

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