Free KCSE Physics Topical Questions KNEC Standards

K.C.S.E Physics Q & A - MODEL 2004PP2QN07

12/7/2020

K.C.S.E Physics Q & A - MODEL 2004PP2QN07

a) i) What is photoelectric effect?
ii) You are provided with the following:
a photocell, a source uv light, a rheostat, a source of e.m.f, a milliammeter, a voltmeter and connecting wires. Draw a circuit diagram to show how photoelectric effect may be demonstrated in the laboratory.
b) In a photoelectric effect experiment, a certain surface was illuminated with radiation of different frequencies and the stopping potential determined for each frequency
Table 2 shows the results obtained.

(i) Plot the graph of the graph of stopping potential (y-axis) against frequency.
(ii) Determine Planks Constant, h, and the work function,of the surface given that eVs = hf- hfo where e= 1.6x 10^-19 coulomb and hf = 0(thita)fo is the lowest frequency that can cause photoelectric effect.
c) A surface whose work function = 6.4 x 10^-19 joules is illuminated with light of frequency 3.0 x 10 ¹⁵HZ
Find the maximum Kinetic energy of the emitted photoelectrons (Use the Value of H obtained in b(ii)

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K.C.S.E Physics Q & A - MODEL 2004PP2QN06

12/7/2020

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K.C.S.E Physics Q & A - MODEL 2004PP2QN06

a) You are provided with two identical tuning forks and some plasticine.
Describe how you would demonstrate beats in sound.
b) Fig 8 shows a set up that was used in an experiment to determine the speed of sound air

Turning forks of different frequencies were sounded near the mouth of the open tube and by lowering the reservoir, the list two resonant lengthsL1 L2 were ensured for each frequency.
Table 1 shows the results obtained.

(i) Complete the table. On the grid provided, plot the graph of l2– l1 (y-axis ) against 1/f
(ii) From the graph determine the speed V of sound in air given that
12-11 = v/2r. Therefore V= 2f(12 – 11)
(iii) Explain how resonance is attained in this set up.

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K.C.S.E Physics Q & A - MODEL 2004PP2QN05

12/7/2020

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K.C.S.E Physics Q & A - MODEL 2004PP2QN05

a) Fig 6 shows a simple generator. The coils are rotated in the anticlockwise direction as shown

i) Indicate using an arrow on the figure, the direction of the induced current as the coil passes the position shown.
ii State two ways of increasing the magnitude of the induced current in this type of generator.
iii) On the axes provided, sketch the graph of the induced e.m.f with time.
iv) The section marked XY is cut off and a diode inserted. On the axes provided, sketch the graph of p.d across the resistor R, against time

b) Fig 7 shows pendulum A and pendulum B freely suspended between the poles of identical magnets. Pendulum a is made of thick copper plate while B is made a copper plate with slot

When the two are set to swing, it is observed that A slows down faster then B Explain this observation.
c) An alternating current source has a root-mean-square potential difference of 12,V, Determine the peak value of this potential difference.

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K.C.S.E Physics Q & A - MODEL 2004PP2QN04

12/7/2020

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K.C.S.E Physics Q & A - MODEL 2004PP2QN04

a) Fig 5 shows the displacement time graph of a wave traveling at 200cm/

Determine for the wave the
i) Amplitude
ii) Period
iii) Frequency
iv) Wavelength
b) i) In the space provided below, sketch a labeled diagram to show how pinhole camera forms an image of a vertical object placed in front of the pinhole.
ii) a building standing 200m from a pinhole camera produces on the screen of the camera an image 2.5cm high 5.0cm behind the pinhole. Determine the actual height of the building

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K.C.S.E Physics Q & A - MODEL 2004PP2QN03

12/7/2020

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K.C.S.E Physics Q & A - MODEL 2004PP2QN03

Figure 4 shows the cross-section of a diffusion cloud chamber used to detect radiation from radioactive sources.

a) i) State one function of each of the following:
Alcohol
solid Co2
ii) When radiation from the source enters the chamber, some white traces are observed. Explain how these traces are formed and state how the radiation is identified.
iii) A leaf electroscope can also be used as a detector of radiation. State two advantages of the diffusion cloud chamber over the leaf electroscope as a detector.
b) i) Two samples of the same radioactive material have initial masses M and 2M respectively. On the axes provided, sketch the graph of activity versus time for each sample. Label the graph for each sample.

ii) A radioactive sample of half-life 130 days initially has 1.0 x 10²c radioactive atoms. Determine the number of radioactive atoms that have decayed after 390 days.

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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 2004PP2QN07

K.C.S.E Physics Q & A - MODEL 2004PP2QN07

K.C.S.E Physics Q & A - MODEL 2004PP2QN06

K.C.S.E Physics Q & A - MODEL 2004PP2QN06

K.C.S.E Physics Q & A - MODEL 2004PP2QN05

K.C.S.E Physics Q & A - MODEL 2004PP2QN05

K.C.S.E Physics Q & A - MODEL 2004PP2QN04

K.C.S.E Physics Q & A - MODEL 2004PP2QN04

K.C.S.E Physics Q & A - MODEL 2004PP2QN03

K.C.S.E Physics Q & A - MODEL 2004PP2QN03

ii) A radioactive sample of half-life 130 days initially has 1.0 x 10²c radioactive atoms. Determine the number of radioactive atoms that have decayed after 390 days.

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FORM III - PHYSICS SYLLABUS

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K.C.S.E Physics Q & A - MODEL 2004PP2QN07

K.C.S.E Physics Q & A - MODEL 2004PP2QN07

K.C.S.E Physics Q & A - MODEL 2004PP2QN06

K.C.S.E Physics Q & A - MODEL 2004PP2QN06

K.C.S.E Physics Q & A - MODEL 2004PP2QN05

K.C.S.E Physics Q & A - MODEL 2004PP2QN05

K.C.S.E Physics Q & A - MODEL 2004PP2QN04

K.C.S.E Physics Q & A - MODEL 2004PP2QN04

K.C.S.E Physics Q & A - MODEL 2004PP2QN03

K.C.S.E Physics Q & A - MODEL 2004PP2QN03

ii) A radioactive sample of half-life 130 days initially has 1.0 x 102c radioactive atoms. Determine the number of radioactive atoms that have decayed after 390 days.

Categories

FORM I - PHYSICS SYLLABUS

FORM II - PHYSICS SYLLABUS

FORM III - PHYSICS SYLLABUS

FORM IV - PHYSICS SYLLABUS

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M.A Nyamoti

HIGH SCHOOL RESOURCES

PRIMARY SCHOOL RESOURCES 8-4-4

PRIMARY SCHOOL RESOURCES CBC

COLLEGE RESOURCES

FREE NOVELS

ii) A radioactive sample of half-life 130 days initially has 1.0 x 10²c radioactive atoms. Determine the number of radioactive atoms that have decayed after 390 days.