Microwaves are directed towards the object which reflect them back to the source and are detected and the distance is calculated similarly like the echo. that is distance= velocity of (microwave) x time (seconds).
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The transmitter sends the microwaves which is reflected back by the object and picked by the receiver.The distance is determined from the time taken for the signal to be reflected back since the time speed of the microwave is known.
joseph rimiru answered the question on October 28, 2017 at 09:47
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The element of an electric hot plate has a resistance of 80Ohms. What is the energy dissipated when the element is kept on for 20...
(Solved)
The element of an electric hot plate has a resistance of 80Ohms. What is the energy dissipated when the element is kept on for 20 minutes on a 240V supply
Date posted:
October 27, 2017
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Answers (1)
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A student stands at a distance 400m from a wall and claps two pieces of wood. After the first clap the student claps whenever an...
(Solved)
A student stands at a distance 400m from a wall and claps two pieces of wood. After the first clap the student claps whenever an echo is heard from the wall. Another student starts a stopwatch at the first clap and stops it after the twentieth clap. The stopwatch records a time of 50 seconds. Find the speed of sound.
Date posted:
October 27, 2017
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Answers (1)
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Use the domain theory to explain how an unmagnetized piece of iron becomes magnetized when it is heated and then allowed to cool in a...
(Solved)
Use the domain theory to explain how an unmagnetized piece of iron becomes magnetized when it is heated and then allowed to cool in a magnetized field.
Date posted:
October 27, 2017
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Answers (1)
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Explain why the e.m.f of a dry cell drops if a large current is drawn for a short time and then recovers if allowed to...
(Solved)
Explain why the e.m.f of a dry cell drops if a large current is drawn for a short time and then recovers if allowed to rest.
Date posted:
October 27, 2017
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Answers (1)
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A negatively charged rod is brought rear the cap of a leaf electroscope. The cap is then earthed momentarily by touching with the finger. Finally...
(Solved)
A negatively charged rod is brought rear the cap of a leaf electroscope. The cap is then earthed momentarily by touching with the finger. Finally the rod is withdrawn. The electroscope is found to be positively charged. Explain how this is acquired
Date posted:
October 27, 2017
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Answers (1)
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(a) State any one form of energy (b) An electric crane lifts a load of 2000 kg through a vertical distance of 3.0m in 6...
(Solved)
State any one form of energy
b) An electric crane lifts a load of 2000kg through a vertical distance of 3.0m in 6 seconds Determine:
i) The work done
ii) The power developed by the crane
The efficiency of the crane if it is operated by an electric motor rated 12.5kw.
Date posted:
October 27, 2017
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Answers (1)
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When ice is heated, the temperature remains constant until all ice is melted. Explain this observation.
(Solved)
When ice is heated, the temperature remains constant until all ice is melted. Explain this observation.
Date posted:
October 27, 2017
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Answers (1)
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Using the kinetic theory of gases, explain why air inside a tyre exerts pressure on the walls of the tyre
(Solved)
Using the kinetic theory of gases, explain why air inside a tyre exerts pressure on the walls of the tyre
Date posted:
October 27, 2017
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Answers (1)
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State two advantages of a force pump over lift pump
(Solved)
State two advantages of a force pump over lift pump
Date posted:
October 27, 2017
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Answers (1)
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A box made of glass sides contained a mixture of smoke and air. Bright light was shown on it and viewed through a microscope....
(Solved)
A box made of glass sides contained a mixture of smoke and air. Bright light was shown on it and viewed through a microscope. It is observed that the small bright specks are seen to be moving randomly.
a. What are the bright specks?
b. What cause their movement?
c. If the mixture of smoke and air was cooled, what change or changes would be there in the motion of the specks?
Date posted:
October 26, 2017
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Answers (1)
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The smell of rotten eggs broken in a room spread throughout the room. Explain.
(Solved)
The smell of rotten eggs broken in a room spread throughout the room. Explain.
Date posted:
October 26, 2017
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Answers (1)
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Diffusion support the idea that matter is made up of small particles. Explain.
(Solved)
Diffusion support the idea that matter is made up of small particles. Explain.
Date posted:
October 26, 2017
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Answers (1)
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Some pollen grains were placed in water, explain how their motion supports the idea that matter is in continuous state of motion.
(Solved)
Some pollen grains were placed in water, explain how their motion supports the idea that matter is in continuous state of motion.
Date posted:
October 26, 2017
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Answers (1)
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A roof of a certain house has a surface area of 40000cm^2. If the atmospheric pressure exerted on the roof is 103000 pa, determine the...
(Solved)
A roof of a certain house has a surface area of 40000cm^2. If the atmospheric pressure exerted on the roof is 103000 pa, determine the force on it. (take g=10N/kg)
Date posted:
October 26, 2017
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Answers (1)
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A water manometer was used to measure the pressure of a gas and its height was found to be 40cm. What would be the height...
(Solved)
A water manometer was used to measure the pressure of a gas and its height was found to be 40cm. What would be the height of a manometer whose liquid is glycerine of density 1.26g/cm^3?
Date posted:
October 26, 2017
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Answers (1)
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The barometer in a city was found to be 70 cmHg. Given that the standard atmospheric pressure is 75 cmHg and the density of mercury...
(Solved)
The barometer in a city was found to be 70 cmHg. Given that the standard atmospheric pressure is 75 cmHg and the density of mercury is 13600kg/m^3, determine the altitude of the city. (density of air is 125kg/m^3)
Date posted:
October 26, 2017
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Answers (1)
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A certain hydraulic press, a force of 100N is applied to master piston of area 25cm^2. If it is designed to produce a force...
(Solved)
A certain hydraulic press, a force of 100N is applied to master piston of area 25cm^2. If it is designed to produce a force of 6000N, determine
a. The area of the slave piston.
b. Radius of the slave piston.
Date posted:
October 26, 2017
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Answers (1)
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The atmospheric pressure on a cold day was found to be 760mmHg. Express this in N/m^2(assume density of mercury is 13600kg/m^3 and take g=10N/kg).
(Solved)
The atmospheric pressure on a cold day was found to be 760mmHg. Express this in N/m^2(assume density of mercury is 13600kg/m^3 and take g=10N/kg).
Date posted:
October 26, 2017
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Answers (1)
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A fountain pen is filled up with ink. Explain.
(Solved)
A fountain pen is filled up with ink. Explain.
Date posted:
October 26, 2017
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Answers (1)
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A mercury barometer reads 75cm in a certain place. If one was to use an alcohol barometer, what would be the minimum length used to...
(Solved)
A mercury barometer reads 75cm in a certain place. If one was to use an alcohol barometer, what would be the minimum length used to read the same pressure as the mercury barometer (take =10N/kg, mercury 13600kg/m^3, alcohol = 800kg/m^3)
Date posted:
October 25, 2017
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Answers (1)