impurities weaken/break the thin elastic skin hence lowering surface tension force
mwandavee answered the question on November 3, 2017 at 15:48
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(a) What is meant by specific latent heat of fusion of a substance? (b) In an experiment to determine the specific latent heat of vaporization...
(Solved)
(a) What is meant by specific latent heat of fusion of a substance?
(b) In an experiment to determine the specific latent heat of vaporization of water, steam at 100ºC was passed into water
contained in a well-lagged copper calorimeter. The following measurements were made:
? Mass of calorimeter = 60g
? mass of water + calorimeter = 145g
? Final mass of calorimeter + water + condensed steam = 156g
? Final temperature of the mixture = 48oC
[Specific heat capacity of water = 4200JKg¯¹k¯¹ and specific heat capacity of copper = 390JKg¯¹k¯¹]
Determine the;
(i) mass of condensed steam.
(ii) The heat gained by the water and calorimeter if the initial temperature of the calorimeter and water is 20ºC.
(iii) Given that Lvis the specific latent heat of vaporization of steam, write an expression for the heat given out by steam.
(iv) Determine the value of Lv above (2marks)
(v) State the assumption made in the above experiment
Date posted:
November 2, 2017
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Answers (1)
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A bullet of mass 24g travelling in a horizontal path with a velocity of 450ms-1
strikes a wooden block of wood of mass 976g
resting...
(Solved)
A bullet of mass 24g travelling in a horizontal path with a velocity of 450ms-1
strikes a wooden block of wood of mass 976g
resting on a rough horizontal surface. After impact, the bullet and the block move together for a distance of 7.5m before
coming rest.
(a) Name the type of collision which takes place above (1 mark)
(b) What‘s the velocity of the two bodies when they start sliding (2 marks)
(c) Calculate the force which brings the two bodies to rest (3 marks)
(d) Determine the coefficient of friction between the block and the surface during this motion
Date posted:
November 2, 2017
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Answers (1)
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State what happens to the image when one moves closer to the object when using a pinhole camera.
(Solved)
State what happens to the image when one moves closer to the object when using a pinhole camera.
Date posted:
November 2, 2017
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Answers (1)
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In an experiment to determine the specific latent heat of vaporization of water, steam of mass 20g at 100°C is passed into 200g of water...
(Solved)
In an experiment to determine the specific latent heat of vaporization of water, steam of mass 20g at 100⁰C is passed into 200g of water initially at 40⁰C in a container of negligible heat capacity. The temperature of the water rises to 80⁰C. (take the specific capacity of water 4200J/kg/k and the boiling water as 100⁰C)
i. Determine the specific latent heat of vaporization of water.
ii. What are the two errors in this experiment?
Date posted:
November 2, 2017
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Answers (1)
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Determine the pressure required to compress a gas in a cylinder initially at 40°C and a pressure of 1.03 x10^5pa to one-tenth of its original...
(Solved)
Determine the pressure required to compress a gas in a cylinder initially at 40⁰C and a pressure of 1.03 x10^5pa to one-tenth of its original volume.
Date posted:
November 2, 2017
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Answers (1)
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Bubbles are seen to rise to the surface when the temperature of water reaches it boiling point. (i) What is contained in the bubbles?
(Solved)
Bubbles are seen to rise to the surface when the temperature of water reaches it boiling point.
i. What is contained in the bubbles?
ii. Give a reason why the bubbles rise to the surface only at the boiling point
Date posted:
November 2, 2017
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Answers (1)
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State the four advantages and the two disadvantages of alkaline accumulators over the lead-acid accumulators and the two disadvantages.
(Solved)
State the four advantages and the two disadvantages of alkaline accumulators over the lead-acid accumulators and the two disadvantages.
Date posted:
November 2, 2017
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Answers (1)
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Describe a simple cell.
(Solved)
Describe a simple cell.
Date posted:
November 2, 2017
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Answers (1)
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Apart from metals, give other materials that can conduct electricity
(Solved)
Apart from metals, give other materials that can conduct electricity.
Date posted:
November 2, 2017
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Answers (1)
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In refrigerator, the cool-box is placed near the top. Give a reason for this.
(Solved)
In refrigerator, the cool-box is placed near the top. Give a reason for this.
Date posted:
November 2, 2017
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Answers (1)
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Give a reason why liquids generally expand more than solids.
(Solved)
Give a reason why liquids generally expand more than solids.
Date posted:
November 2, 2017
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Answers (1)
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In deriving the equation of continuity, what three assumptions are made?
(Solved)
In deriving the equation of continuity, what three assumptions are made?
Date posted:
November 2, 2017
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Answers (1)
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Give a reason why most braking systems use liquids and not gases.
(Solved)
Give a reason why most braking systems use liquids and not gases.
Date posted:
November 2, 2017
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Answers (1)
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A partially inflated balloon at sea level becomes fully inflated at higher altitudes. Explain this observation.
(Solved)
A partially inflated balloon at sea level becomes fully inflated at higher altitudes. Explain this observation.
Date posted:
November 2, 2017
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Answers (1)
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Explain how a gas of constant volume exerts pressure on the walls of the container when temperature is increased.
(Solved)
Explain how a gas of constant volume exerts pressure on the walls of the container when temperature is increased.
Date posted:
November 2, 2017
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Answers (1)
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Name the force that is responsible for the spread of water on a glass surface.
(Solved)
Name the force that is responsible for the spread of water on a glass surface.
Date posted:
November 2, 2017
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Answers (1)
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A force can be a pull or push on the body. Name one type of force which is a pull only.
(Solved)
A force can be a pull or push on the body. Name one type of force which is a pull only.
Date posted:
November 2, 2017
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Answers (1)
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Explain why a high jumper flexes his knees when landing on the ground.
(Solved)
Explain why a high jumper flexes his knees when landing on the ground.
Date posted:
November 2, 2017
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Answers (1)
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Four cells have an e.m.f. of 1.5v each. What is the total e.m.f. when the cells are in parallel and which in series.
(Solved)
Four cells have an e.m.f. of 1.5v each. What is the total e.m.f. when the cells are in parallel and which in series.
Date posted:
November 1, 2017
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Answers (1)
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Define the following terms (a) Closed circuit (b) Open circuit (c) Electromotive force (d) Lost volts
(Solved)
Define the following terms
a. Closed circuit
b. Open circuit
c. Electromotive force
d. Lost volts
Date posted:
November 1, 2017
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Answers (1)