The hot air being lighter in weight tends to rise above and escape from the ventilators at the top. This allows the cool air to come in the room to take its place.
Mr Masinde answered the question on April 26, 2018 at 15:54
-
A butcher has a beam balance and masses 0.8 kg and 3 kg. How would he measure 2.2 kg of meat on the balance at once?
(Solved)
A butcher has a beam balance and masses 0.8 kg and 3 kg. How would he measure 2.2 kg of meat on the balance at once?
Date posted:
April 24, 2018
.
Answers (1)
-
A car battery has 12V. 8 dry cells are equal to 12V. Explain why 8 dry cells are not able to start a car?
(Solved)
A car battery has 12V. 8 dry cells are equal to 12V. Explain why 8 dry cells are not able to start a car?
Date posted:
April 24, 2018
.
Answers (1)
-
Given that a kg of copper contains 10^25 atoms and that density of copper is about 9000kg/m^3,estimate the diameter of the copper atom
(Solved)
Given that a kg of copper contains 10^25 atoms and that density of copper is about 9000kg/m^3,estimate the diameter of the copper atom
Date posted:
April 23, 2018
.
Answers (1)
-
A student observed that in the morning that overhead electrical cable is straight? Explain this observation
(Solved)
A student observed that in the morning that overhead electrical cable is straight? Explain this observation.
Date posted:
April 23, 2018
.
Answers (1)
-
A butcher has a beam balance and only two masses of 3.5kg and 5kg.Explain how he can manage to measure for a customer 1.5kg of...
(Solved)
A butcher has a beam balance and only two masses of 3.5kg and 5kg.Explain how he can manage to measure for a customer 1.5kg of meat at once using only the two masses
Date posted:
April 23, 2018
.
Answers (1)
-
A tin containing 5000cm3 of paint has a Mass of 70kg.a)If the mass of the empty tin,including the lid,is 0.5kg,calculate the density of the paint
(Solved)
A tin containing 5000cm3 of paint has a Mass of 70kg.a)If the mass of the empty tin,including the lid,is 0.5kg,calculate the density of the paint
Date posted:
April 23, 2018
.
Answers (1)
-
Explain how the volatile liquid in a refrigerator is made to vaporize in the cooling compartment and to condense in the cooling fins
(Solved)
Explain how the volatile liquid in a refrigerator is made to vaporize in the cooling compartment and to condense in the cooling fins
Date posted:
April 22, 2018
.
Answers (1)
-
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
.
Answers (1)
-
Describe the methods of magnetizing a magnetic material.
(Solved)
Describe the methods of magnetizing a magnetic material.
Date posted:
April 18, 2018
.
Answers (1)
-
What are the applications of photoelectric effect?
(Solved)
What are the applications of photoelectric effect?
Date posted:
April 12, 2018
.
Answers (1)
-
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
.
Answers (1)
-
State any differences between x-rays and cathode rays.
(Solved)
State any differences between x-rays and cathode rays.
Date posted:
April 12, 2018
.
Answers (1)
-
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
.
Answers (1)
-
State the uses of the Cathode Ray Oscilloscope (CRO)
(Solved)
State the uses of the Cathode Ray Oscilloscope (CRO)
Date posted:
April 12, 2018
.
Answers (1)
-
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
.
Answers (1)
-
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
.
Answers (1)
-
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
.
Answers (1)
-
State the main causes of energy losses in transformers:
(Solved)
State the main causes of energy losses in transformers:
Date posted:
April 11, 2018
.
Answers (1)
-
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
.
Answers (1)
-
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
.
Answers (1)