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- The figure below shows a section of a vernier calliper scale.
State the reading of the diameter being measured.(Solved)
The figure below shows a section of a vernier calliper scale.
State the reading of the diameter being measured.
Date posted: May 30, 2019. Answers (1)
- A radioactive element X of half-life of 28 days decay to element Y. A sample of X of mass 16g is kept in a container.
Assuming...(Solved)
A radioactive element X of half-life of 28 days decay to element Y. A sample of X of mass 16g is kept in a container.
Assuming Y is stable, determine the mass of Y that will be found in the containers after 112 days.
Date posted: May 30, 2019. Answers (1)
- The figure below shows a ray of white light dispersed in a triangular prism. The speed of violet light in the prism in 1.88 ×...(Solved)
The figure below shows a ray of white light dispersed in a triangular prism. The speed of violet light in the prism in 1.88 × 108m/s.
a) Explain how glass disperses white light into red and violet bands.
b) Determine the refractive index of the prism material for light (take speed of light in vacuum = 3×108m/s
c) Show on the figure the critical angle C for violet light and determine its value.
d) Given that r =21.5° determine the angle
e) On the same figure, sketch the part of red light after white light strikes the prism if the prism was replaced by another of
similar shape but lower refractive index. (Use a dotted line for the answer)
Date posted: May 30, 2019. Answers (1)
- Determine the cost of using an electric iron rated 1500W, for a total of 30 hours given that the cost of electricity per kwhis kshs...(Solved)
Determine the cost of using an electric iron rated 1500W, for a total of 30 hours given that the cost of electricity per kwh is kshs 8.
Date posted: May 30, 2019. Answers (1)
- A house has four lamps rated (60W, 240V), a cooker rated (5kw, 240V), and an iron box rated (1kW, 240V). All are used 3.5 hours...(Solved)
A house has four lamps rated (60W, 240V), a cooker rated (5kw, 240V), and an iron box rated (1kW, 240V). All are used 3.5 hours a day. Calculate the monthly cost for electricity for the owner at the rate of 13.5 cents/ KWhr.
Date posted: May 30, 2019. Answers (1)
- Figure below shows a simple barometer.
a) What is the region A?
b) What keeps the mercury in the tube?
c) What is the value of the...(Solved)
Figure below shows a simple barometer.
a) What is the region A?
b) What keeps the mercury in the tube?
c) What is the value of the atmospheric pressure being shown by the barometer?
d) What would happen to the reading if the barometer were taken up a high mountain.
e) Give a reason for (d) above.
Date posted: May 30, 2019. Answers (1)
- The diagram below shows a section of a micrometer screw gauge.
The thimble of the micrometer screw gauge is rotated through two and half revolutions in...(Solved)
The diagram below shows a section of a micrometer screw gauge.
The thimble of the micrometer screw gauge is rotated through two and half revolutions in the clockwise direction in order to measure the diameter of a marble. State the diameter of the marble if the instrument had a negative error of
0.03mm.
Date posted: May 30, 2019. Answers (1)
- The primary coil of a transformer has 1200 turns and the secondary coil has 60 turns. The transformer is connected to a 240 V a.c source. (i) The output...(Solved)
The primary coil of a transformer has 1200 turns and the secondary coil has 60 turns. The transformer is connected to a 240V a.c source.
i) The output voltage.
ii) The output current when the primary coil has a current of 0.5A (Assume there is no energy losses)
iii) One of the primary ways in which power is lost in transformers is through eddy currents. State how eddy currents can be
minimized.
Date posted: May 30, 2019. Answers (1)
- In an experiment to determine the speed of sound, an observer stood in front of a high wall at a distance of 80m. He
clapped two...(Solved)
In an experiment to determine the speed of sound, an observer stood in front of a high wall at a distance of 80m. He
clapped two boards together at such a rate that each clap coincided with the echo from the wall. A second observer noted
a time of 9.5 seconds starting with first clap and ending with the 21st clap.
i) Calculate the speed of sound under these conditions.
ii) Describe one probable source of error in this experiment.
iii) State one way in which sound wave differ from light waves.
Date posted: May 30, 2019. Answers (1)
- The speed of sound in air determined on a warm day is 330m/s. Explain any difference you would expect in the results if
the measurement is...(Solved)
The speed of sound in air determined on a warm day is 330m/s. Explain any difference you would expect in the results if
the measurement is done on a cold day.
Date posted: May 30, 2019. Answers (1)
- The figure below is a sketch of ripples caused by a vibrator in a ripple tank whose frequency is 50Hz.
Using the above information, determine the...(Solved)
The figure below is a sketch of ripples caused by a vibrator in a ripple tank whose frequency is 50Hz
Using the above information, determine the speed of the wave motion.
Date posted: May 30, 2019. Answers (1)
- A person standing behind a wall hears a bell ringing although he cannot see the bell. What property of sound enables him
to hear the sound?(Solved)
A person standing behind a wall hears a bell ringing although he cannot see the bell. What property of sound enables him
to hear the sound?
Date posted: May 30, 2019. Answers (1)
- Two resistors whose resistance are R and 5ohms are connected in series to a battery of 24V and internal resistance of 1ohms. If
the current in...(Solved)
Two resistors whose resistance are R and 5ohms are connected in series to a battery of 24V and internal resistance of 1ohms. If
the current in the circuit is 3A. Find the value of R.
Date posted: May 30, 2019. Answers (1)
- A wire was connected to a battery and it was found that the energy converted to heat was 30J when 20 coulombs of
charge flowed through...(Solved)
A wire was connected to a battery and it was found that the energy converted to heat was 30J when 20 coulombs of
charge flowed through the wire in 5 seconds
Calculate
i) The p.d. between the ends of the wire.
ii) The current flowing through the wire.
iii) The resistance of the wire.
iv) The power developed in the wire.
Date posted: May 30, 2019. Answers (1)
- Form four students performed an experiment in photoelectric effect and drew the graph below from the data collected.
From the graph determine
i) threshold frequency.
ii) Planks...(Solved)
Form four students performed an experiment in photoelectric effect and drew the graph below from the data collected.
From the graph determine
i) threshold frequency.
ii) Planks constant . (Take charge on an electron, e = 1.6×10-19C)
Date posted: May 30, 2019. Answers (1)
- The figure below shows the construction and circuit of the modern physics X-ray tube.
a) Indicate on the diagram the path of the x-ray beam.
b)...(Solved)
The figure below shows the construction and circuit of the modern physics X-ray tube.
a) Indicate on the diagram the path of the x-ray beam.
b) Name the part marked C and state its function
c) Name the metal used in parts A and B and state why they are suitable for use in the tube.
d) Why are cooling fins necessary?
Date posted: May 30, 2019. Answers (1)
- Explain why it is not advisable to use a 10A fuse for a hair dryer rated 2.5Kw, 240V.(Solved)
Explain why it is not advisable to use a 10A fuse for a hair drier rated 2.5Kw, 240V.
Date posted: May 30, 2019. Answers (1)
- State how polarization is reduced in a simple cell.(Solved)
State how polarization is reduced in a simple cell.
Date posted: May 30, 2019. Answers (1)
- Give one reason why sound is not classified as an electromagnetic wave.(Solved)
Give one reason why sound is not classified as an electromagnetic wave.
Date posted: May 30, 2019. Answers (1)
- Find the combined capacitance between points A and B of the arrangement shown in the figure below.(Solved)
Find the combined capacitance between points A and B of the arrangement shown in the figure below.
Date posted: May 30, 2019. Answers (1)