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A radioactive sample of half-life 260 days initially has 2.0 x 1020 radioactive atoms. Calculate the number of atoms that would decay after 780 days.
(Solved)
A radioactive sample of half-life 260 days initially has 2.0 x 1020 radioactive atoms. Calculate the number of atoms that would decay after 780 days.
Date posted:
September 11, 2019
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Answers (1)
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Two magnets A and B in the figure below were brought from a point high above a table towards a steel pin.State with a reason...
(Solved)
Two magnets A and B in the figure below were brought from a point high above a table towards a steel pin.
State with a reason which magnet will attract the pin at a bigger height above the table.
Date posted:
September 11, 2019
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Answers (1)
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In a cathode ray oscilloscope the time base is set at 25ms/mm. Given that crest to crest of a signal covers a length of 6cm,...
(Solved)
In a cathode ray oscilloscope the time base is set at 25ms/mm. Given that crest to crest of a signal covers a length of 6cm, determine the frequency of the signal.
Date posted:
September 11, 2019
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Answers (1)
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The chart below shows an arrangement of different parts of the electromagnetic spectrum.Name the radiation represented by B.
(Solved)
The chart below shows an arrangement of different parts of the electromagnetic spectrum.Name the radiation represented by B.
Date posted:
September 11, 2019
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Answers (1)
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A positively charged rod is brought close to the cap of a gold leaf electroscope, it is observed that the gold leaf diverged further. Explain...
(Solved)
A positively charged rod is brought close to the cap of a gold leaf electroscope, it is observed that the gold leaf diverged further. Explain this observation.
Date posted:
September 11, 2019
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Answers (1)
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The figure below shows a circuit contains a battery of cells V, a 3A fuse, F, a switch S, and two identical lamps L1 and...
(Solved)
The figure below shows a circuit contains a battery of cells V, a 3A fuse, F, a switch S, and two identical lamps L1 and L2. A current of 2A flows through lamp L2 when the switch is open.Explain why the fuse may blow when the switch is closed.
Date posted:
September 11, 2019
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Answers (1)
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The figure below shows a set-up used to investigate Charles Law.
(Solved)
The figure below shows a set-up used to investigate Charles Law.
(i) State one missing item in the set-up.
(ii) Name two measurements to be taken in this experiment.
(iii) Explain how the measurements stated above may be used to investigate Charles Law.
Date posted:
September 11, 2019
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Answers (1)
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A small pump develops an average power of 100w it raises water from a borehole to a point 10M above the water level.Calculate the mass...
(Solved)
A small pump develops an average power of 100w it raises water from a borehole to a point 10M above the water level.Calculate the mass of water delivered in 30 minutes.
Date posted:
September 11, 2019
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Answers (1)
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Using the pulley system shown below a mass of 10kg is raised 2M by effort of 80N.
(Solved)
Using the pulley system shown below a mass of 10kg is raised 2M by effort of 80N.
(i) Calculate the distance the effort moves.
(ii) How much potential energy does the load gain.
(iii) How much work is done by the effort?
(iv) What is the efficiency of these pulleys?
Date posted:
September 11, 2019
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Answers (1)
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The figure below shows an object of mass 1kg whirled in a vertical circle of radius 0.5m at a uniform speed of 5m/s.
(Solved)
The figure below shows an object of mass 1kg whirled in a vertical circle of radius 0.5m at a uniform speed of 5m/s.
(i) Determine:
I the centripetal force on the object.
II the tension in the string when the object is at A.
III the tension in the string when the object is at B.
(ii) The speed of rotation is gradually increased until the string snaps. At what point is the string likely to snap. Explain.
Date posted:
September 11, 2019
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Answers (1)
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A rock of mass 150kg moving at 10m/s collides with a stationary rock of mass 100kg. They fuse after collision.Determine the
(i) Total momentum before collision....
(Solved)
A rock of mass 150kg moving at 10m/s collides with a stationary rock of mass 100kg. They fuse after collision.Determine the
(i) Total momentum before collision.
(ii) Total momentum after collision.
(iii) Their common velocity after collision.
Date posted:
September 11, 2019
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Answers (1)
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The figure below shows a balloon filled with air.When the mouth is suddenly opened, the balloon moves in the direction shown by the arrow. Explain...
(Solved)
The figure below shows a balloon filled with air.When the mouth is suddenly opened, the balloon moves in the direction shown by the arrow. Explain that observation.
Date posted:
September 11, 2019
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Answers (1)
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Give a reason why the inside of a helmet is lined with sponge.
(Solved)
Give a reason why the inside of a helmet is lined with sponge.
Date posted:
September 11, 2019
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Answers (1)
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State one application of cooling caused by evaporation.
(Solved)
State one application of cooling caused by evaporation.
Date posted:
September 11, 2019
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Answers (1)
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A certain powder of mass 100g was heated in a container by an electric heater rated 100w for some time. The graph below shows the...
(Solved)
A certain powder of mass 100g was heated in a container by an electric heater rated 100w for some time. The graph below shows the variation of the temperature of the powder with time.
Use the graph to:
(i) Determine the melting point of the powder
(ii) Determine the quantity of heat supplied by the heater from the time the powder starts to melt to the time it has melted.
(iii) Determine the specific latent heat of fusion of the powder assuming the container absorbs negligible amount of heat.
Date posted:
September 11, 2019
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Answers (1)
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The figure below represents a block of uniform cross-sectional area 6.0cm² floating on two liquids A and B. The length of the block in each...
(Solved)
The figure below represents a block of uniform cross-sectional area 6.0cm² floating on two liquids A and B. The length of the block in each liquid is shown.
Given that the density of liquid A is 800kg/m³ and that of liquid B is 1000kg/m³
determine.
(i) Weight of liquid A displaced.
(ii) Weight of liquid B displaced.
(iii) Density of the block.
Date posted:
September 11, 2019
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Answers (1)
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The figure below shows two forces F1 and F2 acting on an object.Show on the same figure the resultant force.
(Solved)
The figure below shows two forces F1 and F2 acting on an object.Show on the same figure the resultant force.
Date posted:
September 11, 2019
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Answers (1)
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An aircraft 320m from the ground travelling horizontally at 50m/s releases a bomb. Calculate the horizontal distance covered by the bomb from the point of...
(Solved)
An aircraft 320m from the ground travelling horizontally at 50m/s releases a bomb. Calculate the horizontal distance covered by the bomb from the point of release (ignore air resistance and g = 10m/s²).
Date posted:
September 11, 2019
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Answers (1)
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A cork enclosing steam in a boiler is held down by the system shown below.
(Solved)
A cork enclosing steam in a boiler is held down by the system shown below.
If the area of the cork is 20cm², and the force F is 300N, determine the pressure of the steam in the boiler.
Date posted:
September 11, 2019
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Answers (1)
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The figure below shows a solid sphere with its centre of gravity marked with a dot. The sphere is rolled on a horizontal ground and...
(Solved)
The figure below shows a solid sphere with its centre of gravity marked with a dot. The sphere is rolled on a horizontal ground and comes to rest after Some time.Sketch the sphere and mark with a dot the most likely position of the c.o.g after it comes to rest.
Date posted:
September 11, 2019
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Answers (1)