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Calculate the cost of using the following appliances in one month (30 days ) if the company rate is ksh. 9.50 per unit.
i) A 2000W...
(Solved)
Calculate the cost of using the following appliances in one month (30 days ) if the company rate is ksh. 9.50 per unit.
i) A 2000W water heater for 2 hours per day.
ii) A 75W bulb for 10 hour per day.
iii) A 1500W electric iron for 1 hour per day.
Date posted:
May 25, 2019
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Answers (1)
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A transformer with 2000 turns in the primary circuit and 150 turns in the secondary circuit has its primary circuit connected to a 800V a.c...
(Solved)
A transformer with 2000 turns in the primary circuit and 150 turns in the secondary circuit has its primary circuit connected to a 800V a.c source. It is found that when a heater is connected to the secondary circuit, it produced heat at the rate of 1000W. Assuming 100% efficiency, determine the;
i) Voltage in the secondary circuit.
ii) Current in the primary circuit.
iii) Current in the secondary circuit.
iv) State the type of transformer represented above.
Date posted:
May 25, 2019
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Answers (1)
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A boy watching fireworks display sees the light from an explosion and hears the sound 2.5 seconds later. Determine how far is the explosion. (Speed...
(Solved)
A boy watching fireworks display sees the light from an explosion and hears the sound 2.5 seconds later. Determine how far is the explosion. (Speed of sound in air 330m/s).
Date posted:
May 25, 2019
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Answers (1)
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Figure below shows a path of a ray of light through a rectangular block of Perspex placed in air.
Calculate the refractive index of Perpex.
(Solved)
Figure below shows a path of a ray of light through a rectangular block of Perspex placed in air.
Calculate the refractive index of Perpex.
Date posted:
May 25, 2019
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Answers (1)
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An electric heater is found to have a resistance of 950 ohms when operating normally on a 240V mains. Find the power rating of the...
(Solved)
An electric heater is found to have a resistance of 950Ω when operating normally on a 240V mains. Find the power rating of the heater.
Date posted:
May 25, 2019
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Answers (1)
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Figure below shows a ray of light incident along the normal. The mirror is rotated at an angle of 15o in a clockwise direction without...
(Solved)
Figure below shows a ray of light incident along the normal. The mirror is rotated at an angle of 15o in a clockwise direction without changing the position of the incident ray,
Determine the angle between the reflected ray and the incident ray.
Date posted:
May 25, 2019
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Answers (1)
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The figure below shows water waves of different wave length incident on aperture which is greater than the wavelength of the wave.Complete the diagram...
(Solved)
The figure below shows water waves of different wavelength incident on aperture which is greater than the wave length of the wave.
Complete the diagram to show the pattern of the wave beyond the aperture.
Date posted:
May 25, 2019
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Answers (1)
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Figure below shows an object O placed in front of a plane mirror.
On the diagram, draw rays to locate the position of the image I,...
(Solved)
Figure below shows an object O placed in front of a plane mirror.
On the diagram, draw rays to locate the position of the image I, as seen from the eye, E.
Date posted:
May 25, 2019
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Answers (1)
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A balloon weighs 10N and has a gas capacity of 2m3. The gas in the balloon has a density of 0.1kg/m3.
If density of air is...
(Solved)
A balloon weighs 10N and has a gas capacity of 2m3. The gas in the balloon has a density of 0.1kg/m3.
If density of air is 1.3kgm-3, calculate the resultant force of the balloon when it is floating in air.
Date posted:
May 25, 2019
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Answers (1)
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A piece of sealing wax, weight 3N in air and 0.22N when immersed in water, calculate the density of the wax.
(Solved)
A piece of sealing wax, weight 3N in air and 0.22N when immersed in water, calculate the density of the wax.
Date posted:
May 25, 2019
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Answers (1)
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A block of wood measuring 0.8m by 0.5m by 2m floats in water. 1.2m of the block is submerged.
(i) Determine the weight of the water...
(Solved)
A block of wood measuring 0.8m by 0.5m by 2m floats in water. 1.2m of the block is submerged.
(i) Determine the weight of the water displaced.
(ii) Find the force required to just make the block fully submerged.
Date posted:
May 25, 2019
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Answers (1)
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A glass capillary contains enclosed air by a thread of mercury 15cm long when the tube is horizontal, the length of the enclosed air column...
(Solved)
A glass capillary contains enclosed air by a thread of mercury 15cm long when the tube is horizontal, the length of the enclosed air column is 24cm as shown.
(i) What is the length of the enclosed air column when the tube is vertical with the open end uppermost if the atmospheric pressure is 750mmHg?
(ii) What is the length of the enclosed air column when the tube is vertical with the closed end upper most if the atmospheric pressure is 750mmHg.
(iii) Explain why the mercury does not run out when the tube is vertical with the closed end uppermost.
Date posted:
May 25, 2019
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Answers (1)
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The figure below shows an inclined plane, a trolley of mass 60kg being pulled up the slope by a force of 200N parallel to the...
(Solved)
The figure below shows an inclined plane, a trolley of mass 60kg being pulled up the slope by a force of 200N parallel to the slope. The trolley is moved from X to Y.
Determine the
(i) Work output of the system.
(ii) Work input of the system.
(iii) The frictional force between the wheels of the trolley and the inclined plane.
(iv) The efficiency of the system.
(v) The velocity ratio of the system.
Date posted:
May 25, 2019
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Answers (1)
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A uniform metal strip is 3.0cm wides 0.6cm thick and 100cm long. The density of the metal is 2.7g/cm3.
Determine the weight of the metal strip.
(Solved)
A uniform metal strip is 3.0cm wides 0.6cm thick and 100cm long. The density of the metal is 2.7g/cm3.
Determine the weight of the metal strip.
Date posted:
May 25, 2019
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Answers (1)
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The graph (curve) below show the variation of force against extension (cm) of two spiral springs of same material, same wire thickness length but of...
(Solved)
The graph (curve) below show the variation of force against extension (cm) of two spiral springs of same material, same wire thickness length but of different diameters (one large and the other small). Identify which graph (A or B) represents which spring.
Date posted:
May 25, 2019
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Answers (1)
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When the flask is placed in iced water the level on water rose and then fell. Explain this observation.
(Solved)
When the flask is placed in iced water the level on water rose and then fell. Explain this observation.
Date posted:
May 25, 2019
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Answers (1)
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A 20kw immersion water heater is used to heat 5.0 x 10-3m3 of water from 23oC to 100oC. Given that 30% of heat is lost...
(Solved)
A 20kw immersion water heater is used to heat 5.0 x 10-3m3 of water from 23oC to 100oC. Given that 30% of heat is lost to the surroundings, determine the time used in heating the water.
Date posted:
May 25, 2019
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Answers (1)
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An aircraft 300m from the ground traveling horizontally at 400m/s releases a parcel. Calculate the horizontal distance covered by the parcel from the point of...
(Solved)
An aircraft 300m from the ground traveling horizontally at 400m/s releases a parcel. Calculate the horizontal distance covered by the parcel from the point of release.(Ignore air resistance).
Date posted:
May 25, 2019
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Answers (1)
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In an experiment a crystal of potassium permanganate was placed in water as shown below.
After sometime, it was observed that the water turned purple. Explain...
(Solved)
In an experiment a crystal of potassium permanganate was placed in water as shown below.
After sometime, it was observed that the water turned purple. Explain this observation.
Date posted:
May 25, 2019
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Answers (1)
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The figure below shows a capillary tube placed in a trough of mercury.
Give a reason why the level of mercury in a capillary is lower...
(Solved)
The figure below shows a capillary tube placed in a trough of mercury.
Give a reason why the level of mercury in a capillary is lower than in the beaker.
Date posted:
May 25, 2019
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Answers (1)