The liquid acquires latent heat from the items in the cooling compartment and changes to vapour. It moves through the coil as the copper fins conducts heat away from the liquid to the environment.
Edwinnyongesa8 answered the question on May 5, 2018 at 16:34
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Given that a kg of copper contains about 10^25 atoms and that the density of copper is about 9000kg/m^3.estimate the diameter of the copper atoms?State...
(Solved)
Given that a kg of copper contains about 10^25 atoms and that the density of copper is about 9000kg/m^3. Estimate the diameter of the copper atoms?
State the assumption made.
Date posted:
April 19, 2018
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Answers (1)
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Describe the methods of magnetizing a magnetic material.
(Solved)
Describe the methods of magnetizing a magnetic material.
Date posted:
April 18, 2018
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Answers (1)
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What are the applications of photoelectric effect?
(Solved)
What are the applications of photoelectric effect?
Date posted:
April 12, 2018
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Answers (1)
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The threshold wavelength of a photoemissive surface is 0.45µm. calculate:
a. The threshold frequency of the surface.
b. The workfunction of the surface in eV.
c. The minimum...
(Solved)
The threshold wavelength of a photoemissive surface is 0.45µm. calculate:
a. The threshold frequency of the surface.
b. The workfunction of the surface in eV.
c. The minimum speed with which a photoelectron is emitted if the frequency of the radiation is 7.5x1014Hz.
Date posted:
April 12, 2018
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Answers (1)
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State any differences between x-rays and cathode rays.
(Solved)
State any differences between x-rays and cathode rays.
Date posted:
April 12, 2018
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Answers (1)
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An x-ray tube operates at 10kV and a current of 15mA. Calculate the number of electrons hitting the target per second.
(Solved)
An x-ray tube operates at 10kV and a current of 15mA. Calculate the number of electrons hitting the target per second.
Date posted:
April 12, 2018
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Answers (1)
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State the uses of the Cathode Ray Oscilloscope (CRO)
(Solved)
State the uses of the Cathode Ray Oscilloscope (CRO)
Date posted:
April 12, 2018
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Answers (1)
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An electric cooker has an oven rated 3 kW, a grill rated 2 kW and two rings each rated 500 W. The cooker operates from a 240V...
(Solved)
An electric cooker has an oven rated 3 kW, a grill rated 2 kW and two rings each rated 500 W. The cooker
operates from a 24 0V mains. What is the cost of operating all the parts for 5 minutes if electricity costs Sh 1.50 per unit?
Date posted:
April 11, 2018
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Answers (1)
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An electric cooker has an oven rated 3kW, a grill rated 2kW and two rings each rated 500W. The cooker operates from 240V...
(Solved)
An electric cooker has an oven rated 3kW, a grill rated 2kW and two rings each rated 500W. The cooker
operates from 240V mains. Would a 5A fuse be suitable for the cooker assuming that all the parts are switched
on?
Date posted:
April 11, 2018
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Answers (1)
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Some length of a power line has a resistance of 10? and is transmitting 11kV and a current of 1A. If the
voltage is stepped...
(Solved)
Some length of a power line has a resistance of 10Ω and is transmitting 11kV and a current of 1A. If the
voltage is stepped up to 160kV by a transformer, calculate:
a) The initial power loss
b) The power loss after step up
Date posted:
April 11, 2018
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Answers (1)
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State the main causes of energy losses in transformers:
(Solved)
State the main causes of energy losses in transformers:
Date posted:
April 11, 2018
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Answers (1)
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A student designed a transformer to supply a current of 10A at a potential difference of 60V to an electric motor from an ac supply...
(Solved)
A student designed a transformer to supply a current of 10A at a potential difference of 60V to an electric motor from an ac supply of 240V. if the efficiency of the transformer is 80%, calculate:
a) The power supplied to the transformer.
b) The current in the primary coil
Date posted:
April 11, 2018
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Answers (1)
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A bob of mass 1kg is moving in a uniform circular path in a vertical plane of radius 1m. If it is whirled at...
(Solved)
A bob of mass 1kg is moving in a uniform circular path in a vertical plane of radius 1m. If it is whirled at a
frequency of 2 cycles per second, calculate:
a) The tension in the string when the bob is at the top part of the circle
b) Tension when it is at the bottom
c) At what position is the string likely to break? Why?
d) What is the minimum speed required to maintain the string under tension.
Date posted:
April 11, 2018
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Answers (1)
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An object of mass 0.4kg is rotated by a string at a constant speed, v in a vertical circle of radius 1m. If the
minimum...
(Solved)
An object of mass 0.4kg is rotated by a string at a constant speed, v in a vertical circle of radius 1m. If the
minimum tension in the string is 3N, calculate :
a) The speed, v
b) Maximum tension in the string
c) The tension when the string is just horizontal
Date posted:
April 11, 2018
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Answers (1)
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An object of mass 8kg is whirled round rapidly in a vertical circle of radius 2m with a constant speed of
6m/s. Calculate the maximum...
(Solved)
An object of mass 8kg is whirled round rapidly in a vertical circle of radius 2m with a constant speed of
6m/s. Calculate the maximum and minimum tension in the string. Take g=10N/kg
Date posted:
April 11, 2018
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Answers (1)
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A stone of mass 0.6kg attached to a string of length 0.5m is whirled in a horizontal circle at a constant speed. If the maximum...
(Solved)
A stone of mass 0.6kg attached to a string of length 0.5m is whirled in a horizontal circle at a constant
speed. If the maximum tension in the string is 5N before it breaks, calculate:
a) The maximum speed of the stone
b) The maximum number of revolutions per second it can make
Date posted:
April 11, 2018
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Answers (1)
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A car of mass 100kg moves round a circular track of radius 100m with a linear speed of 20m/s. calculate:a) The angular velocityb) The centripetal...
(Solved)
A car of mass 100kg moves round a circular track of radius 100m with a linear speed of 20m/s. calculate:
a) The angular velocity
b) The centripetal force
c) The centripetal acceleration
Date posted:
April 11, 2018
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Answers (1)
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A ray of light from air passes successively through parallel layers of water, oil, glass and then into air again. If the refractive indices...
(Solved)
A ray of light from air passes successively through parallel layers of water, oil, glass and then into air again. If the refractive indices of water, oil and glass are 4/3, 6/5 and 3/2 respectively and the angle of incidence in air is 600.
Calculate
i) The angle of refraction in water.
ii) The angle of incidence at the oil-glass interface.
Date posted:
April 10, 2018
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Answers (1)
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State the differences between evaporation and boiling
(Solved)
State the differences between evaporation and boiling
Date posted:
April 10, 2018
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Answers (1)
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An aluminium tray of mass 400g containing 300g of water is placed in a refrigerator. After 80 minutes, the tray is removed and it is...
(Solved)
An aluminium tray of mass 400g containing 300g of water is placed in a refrigerator. After 80 minutes, the
tray is removed and it is found that 60g of water remains unfrozen at 0^oC. If the initial temperature of the tray and its contents was 20^oC, determine the average amount of heat removed per minute by the refrigerator. Take s.h.c of aluminium = 900JKg-1K-1, s.h.c of water = 4200JKg-1K-1, s.l.h. of fusion of ice = 3.4*25JKg
Date posted:
April 10, 2018
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Answers (1)