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Air molecules near the earth’s surface are denser than the air molecules further above the earth. When heating by sun heat, they became lighter and move upward not downward.
chrispohmomanyi answered the question on September 20, 2017 at 07:20
- A body in a uniform circular motion experiences acceleration despite moving at a constant
speed. Explain(Solved)
A body in a uniform circular motion experiences acceleration despite moving at a constant
speed. Explain
Date posted: September 20, 2017. Answers (1)
- Calculate the length of a wire required to make a resistor of 0.5 ohms, if the receptivity of the
material is 4.9 x 10^-7 ohm m...(Solved)
Calculate the length of a wire required to make a resistor of 0.5 ohms, if the receptivity of the
material is 4.9 x 10^-7 ohm m and the cross sectional area is 2.0 x 10^-8
Date posted: September 19, 2017. Answers (1)
- The activity of a radioactive substance, initially at 400 counts per second reduces to 50 counts per
second in 72 minutes. Determine the half – life...(Solved)
The activity of a radioactive substance, initially at 400 counts per second reduces to 50 counts per
second in 72 minutes. Determine the half – life of the substance
Date posted: September 19, 2017. Answers (1)
- The primary coils of a transformer has 2000 turns and carries a current of 3A. If the secondary coil
is designed to carry a current of...(Solved)
The primary coils of a transformer has 2000 turns and carries a current of 3A. If the secondary coil
is designed to carry a current of 30A, calculate the maximum number of turns in the secondary
coil.
Date posted: September 19, 2017. Answers (1)
- A heating coil rated 1000 W takes 15 minutes to heat 20kg of a liquid from 26^o C of 42^o C.
Determine the specific heat capacity...(Solved)
A heating coil rated 1000 W takes 15 minutes to heat 20kg of a liquid from 26^o C of 42^o C.
Determine the specific heat capacity of the liquid.
Date posted: September 19, 2017. Answers (1)
- Give one example of a semiconductor and one for a conductor
(Solved)
Give one example of a semiconductor and one for a conductor
Date posted: September 19, 2017. Answers (1)
- Distinguish between semiconductor and conductors(Solved)
Distinguish between semiconductor and conductors
Date posted: September 19, 2017. Answers (1)
- Which instrument which can be used to measure the thickness of the hair(Solved)
Which instrument which can be used to measure the thickness of the hair.
Date posted: September 19, 2017. Answers (1)
- State the accuracy of a vernier caliper.(Solved)
State the accuracy of a vernier caliper.
Date posted: September 19, 2017. Answers (1)
- State the difference between conductors and insulators(Solved)
State the difference between conductors and insulators
Date posted: September 19, 2017. Answers (1)
- Explain why boiling water is not used to sterilize clinical thermometer.(Solved)
Explain why boiling water is not used to sterilize clinical thermometer.
Date posted: September 19, 2017. Answers (1)
- State any two reasons why water is not a suitable thermometric fluid.(Solved)
State any two reasons why water is not a suitable thermometric fluid.
Date posted: September 19, 2017. Answers (1)
- State why concrete is usually reinforced with steel in the construction of beams(Solved)
State why concrete is usually reinforced with steel in the construction of beams.
Date posted: September 19, 2017. Answers (1)
- Explain why trees bends towards a busy highway.(Solved)
Explain why trees bends towards a busy highway.
Date posted: September 19, 2017. Answers (1)
- Differentiate between pressure and force(Solved)
Differentiate between pressure and force
Date posted: September 19, 2017. Answers (1)
- State any two special rays used in the construction of ray diagrams(Solved)
State any two special rays used in the construction of ray diagrams
Date posted: September 19, 2017. Answers (1)
- Electrons emitted from a metal when light of a certain frequency is shone on the metal are
found to have a maximum energy of 8.0 x...(Solved)
Electrons emitted from a metal when light of a certain frequency is shone on the metal are
found to have a maximum energy of 8.0 x 10-19J. If the work function of the metal is 3.2 x 10-19J,
determine the wavelength of the light used.
Date posted: September 19, 2017. Answers (1)
- A car can be brought to rest from a speed of 20 ms-1 in a time of 2s.
(i) Calculate the average deceleration
(ii) If the driver’s...(Solved)
A car can be brought to rest from a speed of 20 ms-1 in a time of 2s.
(i) Calculate the average deceleration
(ii) If the driver’s reaction time is 0.2s, determine the shortest stopping distance
Date posted: September 19, 2017. Answers (1)
- A drinking glass 0.02 kg contains 200gms of water at 20^0 C. A mass of 0.04 kg of ice at 0^0 C is
dropped into the...(Solved)
A drinking glass 0.02 kg contains 200gms of water at 20^0C. A mass of 0.04 kg of ice at 0^0 C is
dropped into the glass. Determine the final temperature of the mixture. Specific heat capacity of
glass = 670kg^-1K^-1. (Give your answer to correct one decimal place)
Date posted: September 19, 2017. Answers (1)
- State how eddy currents are reduced in a transformer(Solved)
How are eddy currents in the transformer minimized?
Date posted: September 19, 2017. Answers (1)