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This is because cold air from outside is denser and therefore enters the rooms. inside the rooms, air is warm and therefore moves upwards and thus can disappear out of the room through the ventilators. Therefore in general, the concept which applies here is that cold air which is dense moves down while warm less dense air moves out through the ventilators.
joseph kieti answered the question on December 7, 2017 at 11:11
- Give the two differences between the cathode ray tube (CRT) of a T.V. and the cathode ray oscilloscope (CRO).(Solved)
Alternating current (a.c.) is used for transmitting electricity over long distance, state the reason.
Date posted: December 4, 2017. Answers (1)
- The follow table shows electric appliances to be used in a home. The electrical rating for each appliance is shown. The fuses available are 5A,...(Solved)
9. The follow table shows electric appliances to be used in a home. The electrical rating for each appliance is shown. The fuses available are 5A, 15A, 30A and 45 A
Appliance-----voltage(V)-----Power(w)
T.V.----------240----------300
Iron box------240----------720
Electrical kettle--240----2400
Determine which one of the fuses is suitable for the house.
Date posted: December 4, 2017. Answers (1)
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Alternating current (a.c.) is used for transmitting electricity over long distance, state the reason.
Date posted: December 4, 2017. Answers (1)
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(ii)How the heating can be minimized.
Date posted: December 4, 2017. Answers (1)
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The primary coil of a transformer has 2000 turns and secondary coil is connect to a 240V a.c. mains supply.
(a)Explain how an e.m.f. is induced in the secondary voltage.
(b)Determine the secondary voltage
Date posted: December 4, 2017. Answers (1)
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In a transformer the ratio of primary to secondary is 1:10. A current of 200mA flow through a 200 ohm resistor in the secondary circuit. Assuming that the transformer is 100% efficient, determine:
a. The secondary voltage.
b. The primary voltage.
c. The primary current.
Date posted: December 4, 2017. Answers (1)
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Date posted: December 4, 2017. Answers (1)
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Explain how the energy losses are reduced in a transform by having :
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b. A laminated core
Date posted: December 4, 2017. Answers (1)
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Date posted: November 30, 2017. Answers (1)
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Date posted: November 30, 2017. Answers (1)
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Date posted: November 30, 2017. Answers (1)
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(Solved)
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Date posted: November 30, 2017. Answers (1)
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Date posted: November 29, 2017. Answers (1)
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Date posted: November 29, 2017. Answers (1)
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Date posted: November 27, 2017. Answers (1)
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Date posted: November 27, 2017. Answers (1)
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Date posted: November 27, 2017. Answers (1)
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Date posted: November 27, 2017. Answers (1)
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Date posted: November 27, 2017. Answers (1)
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Date posted: November 27, 2017. Answers (1)