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(a) State the observation made.
Pollen grains were seen to be moving in constant random motion.
(b) Explain the observation in (a) above.
The grains were being hit continuously by the invisible water molecules which
were also in random motion.
(c) What conclusion can be drawn from the above experiment.
Matter is particulate.
Kavungya answered the question on June 4, 2019 at 07:07
- 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)
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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)
- The figure below shows a uniform rod of height 8cm floating vertically in a beaker containing two immiscible liquids P and Q. The densities of...(Solved)
The figure below shows a uniform rod of height 8cm floating vertically in a beaker containing two immiscible liquids P and Q. The densities of the liquids are 800kg/m³ and 1200g/m³ respectively the cross-sectional area of the rod is 2cm².
Determine
(i) the weight of liquid P displaced by the rod.
(ii) the weight of liquid Q displaced by the rod.
(iii) the mass of the rod.
(iv) the density of the rod.
Date posted: June 3, 2019. Answers (1)
- A car of mass 1200kg is negotiating a curve of radius 45m on a horizontal road. The force of friction between the tyres and the...(Solved)
A car of mass 1200kg is negotiating a curve of radius 45m on a horizontal road. The force of friction between the tyres and the road is 6700N. Determine the maximum speed at which the car can be driven on the curve without going off the road.
Date posted: June 3, 2019. Answers (1)
- The diagram below shows a simplified hydraulic braking system of a car.
(i) State the property of the liquid (oil) that makes its more suitable than...(Solved)
The diagram below shows a simplified hydraulic braking system of a car.
(i) State the property of the liquid (oil) that makes its more suitable than a gas for use as a brake fluid.
(ii) Explain how the system works starting from when the driver presses the foot pedal.
Date posted: June 3, 2019. Answers (1)
- Explain how a person is able to draw milk from a glass using a straw.(Solved)
Explain how a person is able to draw milk from a glass using a straw.
Date posted: June 3, 2019. Answers (1)
- The following figure shows a wheel and axle used to raise a load W by applying an effort F. The radius of the larger wheel...(Solved)
The following figure shows a wheel and axle used to raise a load W by applying an effort F. The radius of the larger wheel is R and the small wheel is y.
Given that v = 5cm and R is 8cm, determine the effort required to raise a load of 20N if the efficiency of the system is 80%.
Date posted: June 3, 2019. Answers (1)
- An immersion heater takes 30 minutes to heat 20kg of water from 250C to 600C. How long would the same heater take to heat the...(Solved)
An immersion heater takes 30 minutes to heat 20kg of water from 250C to 600C. How long would the same heater take to heat the same mass of kerosene through the same temperature range. (Assume no heat is lost to the surrounding).
Specific heat capacity of water = 4200JKgˉ¹Kˉ¹
Specific heat capacity of kerosene = 2200JKgˉ¹Kˉ¹
Date posted: June 3, 2019. Answers (1)