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- Sun’s radiation easily passes through the earth’s atmosphere.
- As it warms up, the earth re-radiates energy of longer wavelength (lower energy/
shorter frequency) which is absorbed by water vapour, CO2 and other gases.
- The warm atmosphere in turn radiates back to the earth so making it warmer than
it would otherwise be.
Kavungya answered the question on June 4, 2019 at 07:29
- The bicycle pump shown in Figure below is one of the applications of pressure in
gases.
Explain how the leather washer functions during;
(a) backstroke
(b) forward stroke(Solved)
The bicycle pump shown in Figure below is one of the applications of pressure in
gases.
Explain how the leather washer functions during;
(a) backstroke
(b) forward stroke
Date posted: June 4, 2019. Answers (1)
- The diagram below shows a spiral spring when not compressed and when
compressed by a mass of 4.0kg.
Determine the elastic potential energy stored by the compressed...(Solved)
The diagram below shows a spiral spring when not compressed and when
compressed by a mass of 4.0kg.
Determine the elastic potential energy stored by the compressed spring in (b).
Date posted: June 4, 2019. Answers (1)
- A smooth wooden plane is inclined at an angle of 300 to the horizontal as shown in Figure 5 below. An object of mass 10kg...(Solved)
A smooth wooden plane is inclined at an angle of 300 to the horizontal as shown in Figure 5 below. An object of mass 10kg is pulled steadily up the plane by a force of 60N. Determine;
(a) the velocity ratio of the inclined plane.
(b) efficiency of the system.
Date posted: June 4, 2019. Answers (1)
- The figure below shows a rubber bladder filled with air and fixed at the bottom of a
water container and held with a cotton string.
State and...(Solved)
The figure below shows a rubber bladder filled with air and fixed at the bottom of a
water container and held with a cotton string.
State and explain the observation made when water is heated gently for a few
minutes.
Date posted: June 4, 2019. Answers (1)
- An immersion heater consumes a voltage of 240V and a current of 10A. If it is used to heat 5kg of water at 200C, find...(Solved)
An immersion heater consumes a voltage of 240V and a current of 10A. If it is used to heat 5kg of water at 200C, find the final temperature of water after 7 minutes. (Take the specific heat capacity of water = 4200 J/kgk)
Date posted: June 4, 2019. Answers (1)
- A student observed some pollen grains on the surface of water in a beaker with the
help of hand lens as shown below.
(a) State the observation...(Solved)
A student observed some pollen grains on the surface of water in a beaker with the
help of hand lens as shown below.
(a) State the observation made.
(b) Explain the observation in (a) above.
(c) What conclusion can be drawn from the above experiment.
Date posted: June 4, 2019. Answers (1)
- A uniform bar is pointed at a point 30cm from one end. A force of 12N at the shorter
end keeps the bar in equilibrium. If...(Solved)
A uniform bar is pointed at a point 30cm from one end. A force of 12N at the shorter
end keeps the bar in equilibrium. If the length of the bar is 1 metre, determine the
weight w, of the bar.
Date posted: June 4, 2019. Answers (1)
- The figure below shows a force of 40N acting on a body of mass 4kg. The coefficient of friction between the surfaces is 0.05.
Determine the...(Solved)
The figure below shows a force of 40N acting on a body of mass 4kg. The coefficient of friction between the surfaces is 0.05.
Determine the acceleration of the body.
Date posted: June 4, 2019. Answers (1)
- Define a free fall.(Solved)
Define a free fall.
Date posted: June 4, 2019. Answers (1)
- The figure below shows a ray of light incident at an angle of 35.60 at point D on the first face of a glass prism...(Solved)
The figure below shows a ray of light incident at an angle of 35.60 at point D on the first face of a glass prism ABC. The refractive index of the prism is 1.6.
(i) Determine the angle of refraction at point D.
(ii) Find the angle of incidence of the refracted ray on the face AC to 1 decimal point.
(iii) Complete the ray diagram to show the emergent ray from the face AC.
(iv) State two conditions necessary for total internal reflection to occur.
Date posted: June 3, 2019. Answers (1)
- A heater is rated 2000W is used to heat water for 5 hours. Calculate the cost of electricity at Ksh.6.70 per unit.(Solved)
A heater is rated 2000W is used to heat water for 5 hours. Calculate the cost of electricity at Ksh.6.70 per unit.
Date posted: June 3, 2019. Answers (1)
- An object of height 10.5cm stands before a diverging lens of focal length 20cm and a distance of 10cm from the lens. Determine;
(i) image distance....(Solved)
An object of height 10.5cm stands before a diverging lens of focal length 20cm and a distance of 10cm from the lens. Determine;
(i) image distance.
(ii) height of the image.
(iii) magnification.
Date posted: June 3, 2019. Answers (1)
- The figure below shows an object in front of lens.
(i) Using rays locate the image as seen by observer, E.
(ii) Give one application of...(Solved)
The figure below shows an object in front of lens.
(i) Using rays locate the image as seen by observer, E.
(ii) Give one application of such a lens as used above.
(iii) Write three similarities between an eye and a camera.
Date posted: June 3, 2019. Answers (1)
- The work function of a clean metal surface is 7.5eV. Calculate.
(i) The minimum frequency of radiation that will cause the emission of electrons from the...(Solved)
The work function of a clean metal surface is 7.5eV. Calculate.
(i) The minimum frequency of radiation that will cause the emission of electrons from the surface. (Plank’s constant h = 6.63 x 10-34Js, electronic charge e = 1.6 x 10-19C).
(ii) The maximum energy of the electrons emitted when the surface is illuminated with a radiation of frequency 2.0 x 1015HZ.
Date posted: June 3, 2019. Answers (1)
- The graph below show stopping potential Vs against frequency f. (Take C = 3.0 x 108ms¯¹).
Use the graph to determine:-
(i) the threshold wavelength.
(ii) Planck’s...(Solved)
The graph below show stopping potential Vs against frequency f. (Take C = 3.0 x 108msˉ¹).
Use the graph to determine:-
(i) the threshold wavelength.
(ii) Planck’s constant.
(iii) the work function of the metal.
Date posted: June 3, 2019. Answers (1)
- Four capacitor are connected as shown.
Calculate the effective capacitance between A and B.(Solved)
Four capacitor are connected as shown.
Calculate the effective capacitance between A and B.
Date posted: June 3, 2019. Answers (1)
- Sketch a circuit diagram to show how two diodes can be used as a current full wave rectifier.(Solved)
Sketch a circuit diagram to show how two diodes can be used as a current full wave rectifier.
Date posted: June 3, 2019. Answers (1)
- A ray of light is incident on a plane mirror as shown.
(a) What will be the angle through which the reflected ray rotates if the...(Solved)
A ray of light is incident on a plane mirror as shown.
(a) What will be the angle through which the reflected ray rotates if the mirror is rotated anticlockwise through an angle of 350?
(b) What would be the new angle of reflection?
Date posted: June 3, 2019. Answers (1)
- A radioactive substance decays as shown below.
How many alpha and beta particles are emitted?(Solved)
A radioactive substance decays as shown below.
How many alpha and beta particles are emitted?
Date posted: June 3, 2019. Answers (1)
- What is the voltage output for the cell arrangement below?(Solved)
What is the voltage output for the cell arrangement below?
Date posted: June 3, 2019. Answers (1)