V = f x wavelength = 20000Hz x 0.075m = 1500 but V = $\frac{d}{t}$ = $\frac{2d}{3}$ (echo)$\rightarrow$ 2d = 4500 $\rightarrow$ d = 2250 m
johnmulu answered the question on February 11, 2017 at 08:44
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The audible frequency range for a certain person is 30 Hz and 16, 500 Hz. Determine the largest wavelength of sound in air the person can detect
(Solved)
The audible frequency range for a certain person is 30 Hz and 16, 500 Hz. Determine the largest wavelength of sound in air the person can detect.
(Speed of sound in air = 330m/s)
Date posted:
February 11, 2017
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Answers (1)
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Water waves are observed as they pass a fixed point at a rate of 30 crests per minute. A particular wave crest takes 2s to travel between two fixed points 6m apart.
(Solved)
Water waves are observed as they pass a fixed point at a rate of 30 crests per minute. A particular wave crest takes 2s to travel between two fixed points 6m apart.
Determine for the wave:
i) The frequency
ii) The wavelength
Date posted:
February 11, 2017
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Answers (1)
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Calculate the wavelength of the KBC FM radio wave transmitted at a frequency of 95.6 Mega Hertz
(Solved)
Calculate the wavelength of the KBC FM radio wave transmitted at a frequency of 95.6 Mega Hertz.
Date posted:
February 11, 2017
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Answers (1)
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A spring extends by 6 cm when supporting a mass of 0.06 kg on earth. When the spring is used to support the same mass on the moon, it extends by 1 cm
(Solved)
A spring extends by 6 cm when supporting a mass of 0.06 kg on earth. When the spring is used to support the same mass on the moon, it extends by 1 cm. Determine the moon's gravitational strength. (Take gravitational field strength on earth as 10 Nkg-1)
Date posted:
February 11, 2017
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Answers (1)
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(Solved)
State Hooke's law.
Date posted:
February 11, 2017
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Answers (1)
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A lady holds a large concave of focal length 1 m, 80 cm from her face. State two characteristics of her image in the mirror
(Solved)
A lady holds a large concave of focal length 1 m, 80 cm from her face. State two characteristics of her image in the mirror
Date posted:
February 7, 2017
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Answers (1)
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A person carrying a heavy luggage using one hand leans away from the luggage. State the reason for this
(Solved)
A person carrying a heavy luggage using one hand leans away from the luggage. State the reason for this.
Date posted:
February 7, 2017
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Answers (1)
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(Solved)
State the principle of moments
Date posted:
February 7, 2017
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Answers (1)
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Derive an expression for obtaining the diameter, d of a molecule of oil
(Solved)
An oil drop of volume V m3 introduced on the surface of water spreads to form patch whose area is Am2. Derive an expression for obtaining the diameter, d of a molecule of oil.
Date posted:
February 7, 2017
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Answers (1)
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In an experiment to estimate the diameter of an oil molecule, an oil drop of diameter 0.05 cm spreads over a circular patch whose diameter is 20 cm
(Solved)
In an experiment to estimate the diameter of an oil molecule, an oil drop of diameter 0.05 cm spreads over a circular patch whose diameter is 20 cm.
Determine i) the volume of the oil drop
ii) The area of the patch covered by the oil
iii) The diameter of the oil molecule
Date posted:
February 7, 2017
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Answers (1)
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State the assumption made when calculating the size of a molecule in the oil drop experiment
(Solved)
State the assumption made when calculating the size of a molecule in the oil drop experiment
Date posted:
February 7, 2017
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Answers (1)
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An un-magnetized steel rod is clamped facing North-South direction and then hammered repeatedly for some time. When tested, it is found to be magnetized
(Solved)
An un-magnetized steel rod is clamped facing North-South direction and then hammered repeatedly for some time. When tested, it is found to be magnetized. Explain this observation
Date posted:
February 7, 2017
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Answers (1)
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Distinguish between soft and hard magnetic materials
(Solved)
Distinguish between soft and hard magnetic materials
Date posted:
February 7, 2017
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Answers (1)
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Given a bar magnet, an iron bar and a string
i) Describe a simple experiment to distinguish between the magnet and the iron bar
(ii) State...
(Solved)
Given a bar magnet, an iron bar and a string
i) Describe a simple experiment to distinguish between the magnet and the iron bar
(ii) State with reasons the observations that would be made in the experiment.
Date posted:
February 7, 2017
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Answers (1)
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Give reason why attraction in magnetism is not regarded as reliable method of testing for polarity
(Solved)
Give reason why attraction in magnetism is not regarded as reliable method of testing for polarity
Date posted:
February 7, 2017
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Answers (1)
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State the reason for topping up a lead-acid accumulator with distilled water
(Solved)
State the reason for topping up a lead-acid accumulator with distilled water.
Date posted:
February 7, 2017
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Answers (1)
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State one advantage of a lead-acid accumulator over a nickel-iron(NiFe) accumulator
(Solved)
State one advantage of a lead-acid accumulator over a nickel-iron(NiFe) accumulator.
Date posted:
February 7, 2017
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Answers (1)
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A car battery requires topping up with distilled water occasionally. Explain why this is necessary and why distilled water is used
(Solved)
A car battery requires topping up with distilled water occasionally. Explain why this is necessary and why distilled water is used
Date posted:
February 7, 2017
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Answers (1)
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State two advantages of an alkaline battery over a lead acid battery
(Solved)
State two advantages of an alkaline battery over a lead acid battery.
Date posted:
February 7, 2017
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Answers (1)
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State two uses of a charged gold leaf electroscope
(Solved)
State two uses of a charged gold leaf electroscope.
Date posted:
February 7, 2017
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Answers (1)