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i) The leaf falls Collapses
(ii) The electrons are repelled causing the leaf potential to decrease
(iii) NO effect on the leaf. Light emitted by red light doesn’t have enough energy to cause
photoelectric effect.
sharon kalunda answered the question on April 5, 2019 at 05:45
- The graph below represents a graph of stopping potential Vs , V against frequency f, Hz(Solved)
The graph below represents a graph of stopping potential Vs , V against frequency f, Hz
Use the graph to determine:
(i) The threshold frequency of the metal
(ii) Plank’s constant
(iii) Work function of the metal
Date posted: April 5, 2019. Answers (1)
- The figure 7 below shows two blocks of masses M1=1.5kg and M2 = 2.0kg which are in
contact on a frictionless table
A force F=7N acts on...(Solved)
The figure 7 below shows two blocks of masses M1=1.5kg and M2 = 2.0kg which are in
contact on a frictionless table
A force F=7N acts on the bodies, determine the force on mass M2
Date posted: April 5, 2019. Answers (1)
- An object placed 15cm from a convex lens forms an image twice the size of the object.
Determine the focal length of the lens(Solved)
An object placed 15cm from a convex lens forms an image twice the size of the object.
Determine the focal length of the lens
Date posted: April 5, 2019. Answers (1)
- The graph in the diagram in figure below shows the relationship between 1/u and 1/v for a converging lens where u and V are the...(Solved)
The graph in the diagram in figure below shows the relationship between 1/u and 1/v for a converging lens where u and V are the object and image distances respectively.From the graph, determine the focal length f of the lens.
Date posted: April 5, 2019. Answers (1)
- A nail is placed 25cm from the objective lens of focal length 15cm. On the other side of the
objective lens another converging lens of focal...(Solved)
A nail is placed 25cm from the objective lens of focal length 15cm. On the other side of the
objective lens another converging lens of focal length 30cm is placed as the eyepiece. The
distance between the two lenses is 52.5cm
Find: (i) the position of the first image
(ii) the position of the final image from the eye piece lens
Date posted: April 5, 2019. Answers (1)
- A block of mass 5kg rests on an inclined surface as shown in the diagram below:
Determine the static friction on the block(Solved)
A block of mass 5kg rests on an inclined surface as shown in the diagram below:
Determine the static friction on the block
Date posted: April 5, 2019. Answers (1)
- State and explain two features of a hydrometer that make it sensitive in its function(Solved)
State and explain two features of a hydrometer that make it sensitive in its function
Date posted: April 5, 2019. Answers (1)
- The figure below shows a balloon carrying hydrogen gas 3m3 of density 0.09kgm-3. The mass
of the balloon fabric is 2kg and the density of air...(Solved)
The figure below shows a balloon carrying hydrogen gas 3m3 of density 0.09kgm-3. The mass
of the balloon fabric is 2kg and the density of air is 1.25kgm-3
i) Determine the tension in the string
ii) If the string is suddenly cut, calculate the acceleration of the balloon upwards
iii) What is the maximum mass of the equipment the balloon can lift at a constant velocity
Date posted: April 5, 2019. Answers (1)
- A measuring cylinder contains 50cm3 of light oil at 0oC. When a lump of dried ice is placed in
the oil, the total volume is 72cm3....(Solved)
A measuring cylinder contains 50cm3 of light oil at 0oC. When a lump of dried ice is placed in
the oil, the total volume is 72cm3. Determine the density of the ice.
Date posted: April 5, 2019. Answers (1)
- A piece of metal N of mass 2kg weighs 18N in water and 12N in liquid M. Determine the density
of ;
(i) The metal N
(ii) The...(Solved)
A piece of metal N of mass 2kg weighs 18N in water and 12N in liquid M. Determine the density
of ;
(i) The metal N
(ii) The liquid M
Date posted: April 5, 2019. Answers (1)
- A bathroom shower has 200 holes each 2.5mm2 in area. Water flows from a pipe of cross-section
area of 15cm2 at 5m/s to the shower. Determine...(Solved)
A bathroom shower has 200 holes each 2.5mm2 in area. Water flows from a pipe of cross-section
area of 15cm2 at 5m/s to the shower. Determine the speed of the spray.
Date posted: April 5, 2019. Answers (1)
- A ship of mass 1300 tonnes floats on sea water:
(i) What volume of sea water is displaced (Density of sea water is 1025kg/m3)
(ii) Suppose it...(Solved)
A ship of mass 1300 tonnes floats on sea water:
(i) What volume of sea water is displaced (Density of sea water is 1025kg/m3)
(ii) Suppose it sails from sea water to fresh water, what cargo must be removed so that
the same volume of water is displaced? (Density of fresh water = 1000kg/m3
Date posted: April 5, 2019. Answers (1)
- The figure below shows how rays from a distant and near objects are focused inside a human
eye with a certain defect(Solved)
The figure below shows how rays from a distant and near objects are focused inside a human
eye with a certain defect
Name the defect and state the cause of the defect
Date posted: April 4, 2019. Answers (1)
- Sound tends to travel over longer distance at night. Explain(Solved)
Sound tends to travel over longer distance at night. Explain
Date posted: April 4, 2019. Answers (1)
- A boy standing in front of a cliff blows a whistle and hears the echo after 0.5 seconds. He then
moves 17m further away form the...(Solved)
A boy standing in front of a cliff blows a whistle and hears the echo after 0.5 seconds. He then
moves 17m further away form the cliff and blows the whistle again. He now hears the echo after
0.6seconds. Determine the speed of the sound
Date posted: April 4, 2019. Answers (1)
- A girl standing 220m from the foot of a high wall claps her hands and the echo reaches her
1.29 seconds later. Calculate the velocity of...(Solved)
A girl standing 220m from the foot of a high wall claps her hands and the echo reaches her
1.29 seconds later. Calculate the velocity of sound in air using this observation
Date posted: April 4, 2019. Answers (1)
- The human ear can distinguish two sounds as separate only if they need it at least 0.1 seconds
apart. How far from a wall must an...(Solved)
The human ear can distinguish two sounds as separate only if they need it at least 0.1 seconds
apart. How far from a wall must an observer be in order to hear an echo when he shouts.
(Speed of sound = 330m/s)
Date posted: April 4, 2019. Answers (1)
- Figure below shows a ray of light traveling from glass to water.(Solved)
Figure below shows a ray of light traveling from glass to water.
Calculate the angle of incidence if the refractive index of glass and water are 3/2 and 4/3 respectively
Date posted: April 4, 2019. Answers (1)
- The figure below represents a ray of light falling normally on the curved surface of a
semi- circular glass block A at an angle of 32°...(Solved)
The figure below represents a ray of light falling normally on the curved surface of a
semi- circular glass block A at an angle of 32° at O and emerging into air at an angle of 48°
Calculate the absolute refractive index of the glass of which the block is made.
(Assume air is a vacuum)
Date posted: April 4, 2019. Answers (1)
- The refractive index of paraffin is 1.47 and that of glass is 1.55. Determine the critical
angle of a ray of light travelling from glass to...(Solved)
The refractive index of paraffin is 1.47 and that of glass is 1.55. Determine the critical
angle of a ray of light travelling from glass to paraffin
Date posted: April 4, 2019. Answers (1)