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- Kenyatta National Hospital uses x-rays of wavelength 1×10-11m. Calculate the frequency of the x-rays. (Take c=3×108m/s.)(Solved)
Kenyatta National Hospital uses x-rays of wavelength 1×10-11m. Calculate the frequency of the x-rays. (Take c=3×108m/s.)
Date posted: September 10, 2019. Answers (1)
- A ray of light makes an angle of 60° with a plane mirror as shown in the figure below. The mirror is rotated through an...(Solved)
A ray of light makes an angle of 60° with a plane mirror as shown in the figure below. The mirror is rotated through an angle of 20° about the point O in a clockwise direction.
Determine the new angle of reflection.
Date posted: September 10, 2019. Answers (1)
- A mason uses a six wheel pulley system to raise a weight of 250N through a vertical height of 2.5m using the machine.If the mason...(Solved)
A mason uses a six wheel pulley system to raise a weight of 250N through a vertical height of 2.5m using the machine.If the mason pulls using an effort of 500N. Calculate:
i) The velocity ratio of the pulley system.
ii) The work done by the mason.
iii) The useful work done by the pulley system.
iv) The efficiency of the system
Date posted: September 10, 2019. Answers (1)
- The figure below shows a block of mass 50g and density 2000kg/m3 submerged in a certain liquid and suspended from uniform horizontal beam by means...(Solved)
The figure below shows a block of mass 50g and density 2000kg/m3 submerged in a certain liquid and suspended from uniform horizontal beam by means of a string. A mass of 40g suspended from the other end of the beam puts the system in equilibrium
(i) Determine the up-thrust force acting on the block.
(ii) Calculate the density of the liquid.
(iii) Calculate the new balance point of the 50g mass (the 40g mass remains fixed) if the liquid was replace with one whose density was 1500kg/m3.
Date posted: September 10, 2019. Answers (1)
- A bullet moving at a velocity of 350m/s hits a tree trunk of diameter 70cm. It emerge from the opposite side with a velocity of...(Solved)
A bullet moving at a velocity of 350m/s hits a tree trunk of diameter 70cm. It emerge from the opposite side with a velocity of 180m/s. Determine the average deceleration of the bullet in the trunk.
Date posted: September 10, 2019. Answers (1)
- The figure below shows an arrangement to demonstrate diffusion through solids.(Solved)
The figure below shows an arrangement to demonstrate diffusion through solids.
The hydrogen gas is supplied for sometimes then stopped and the beaker removed. State and explain what is likely t be observed when the hydrogen gas supply is stopped.
Date posted: September 10, 2019. Answers (1)
- The figure below shows a simple instrument designed by a student for weighing objects.
a) State what happens if one places an item on the weighing...(Solved)
The figure below shows a simple instrument designed by a student for weighing objects.
a) State what happens if one places an item on the weighing pan.
b) State two properties of water that make it suitable for this purpose.
Date posted: September 10, 2019. Answers (1)
- Xcm3 of substance A which has density 800 kg/m3 is mixed with 1000cm3 of water with a density of 1000kg/m3. The density of the mixture...(Solved)
Xcm3 of substance A which has density 800 kg/m3 is mixed with 1000cm3 of water with a density of 1000kg/m3. The density of the mixture is 960kg/m3. Determine the value of X
Date posted: September 10, 2019. Answers (1)
- Water at 200C falls over a waterfall of height 40m. Calculate the temperature of water at the bottom of the waterfall if 80% of potential...(Solved)
Water at 200C falls over a waterfall of height 40m. Calculate the temperature of water at the bottom of the waterfall if 80% of potential energy at the top is converted into heat energy
Date posted: September 10, 2019. Answers (1)
- An X-ray tube operates with a p.d. of 200kv. Only 0.5% of the kinetic energy of the electrons is converted into X-rays. Calculate the frequency...(Solved)
An X-ray tube operates with a p.d. of 200kv. Only 0.5% of the kinetic energy of the electrons is converted into X-rays. Calculate the frequency of the X-rays produced, take planks constant = 6.63 x 10-34Js.
Date posted: September 10, 2019. Answers (1)
- State what determines the quality of X-rays in an X-rays tube.(Solved)
State what determines the quality of X-rays in an X-rays tube.
Date posted: September 10, 2019. Answers (1)
- State how the following energy losses are minimized in a transformer.
I Eddy current.
II Flux linkage.(Solved)
State how the following energy losses are minimized in a transformer.
I Eddy current.
II Flux linkage.
Date posted: September 10, 2019. Answers (1)
- The figure below shows capacitors connected to 3v supply.(Solved)
The figure below shows capacitors connected to 3v supply.
Calculate:
(i) The combined capacitance.
(ii) The charged stored in the 2.4μF capacitor.
(iii) The charge stored in 2μF capacitor.
Date posted: September 10, 2019. Answers (1)
- Four 40w bulbs and six 100w bulbs were switched on for 2 hours in the morning and 3 hours at night each day for domestic...(Solved)
Four 40w bulbs and six 100w bulbs were switched on for 2 hours in the morning and 3 hours at night each day for domestic use in a certain institution. Find the monthly bill for the consumer given that the cost of electricity in the country is at Sh.6.50 per unit. (Take one month to be of 30 days).
Date posted: September 10, 2019. Answers (1)
- The figure below shows some resistors connected in part of a circuit.Determine the effective resistance.(Solved)
The figure below shows some resistors connected in part of a circuit.Determine the effective resistance.
Date posted: September 10, 2019. Answers (1)
- The figure below shows a large battery connected a resistor of 1000 ohms. The potential difference across the resistor is 50V.(Solved)
The figure below shows a large battery connected a resistor of 1000 ohms. The potential difference across the resistor is 50V.
Determine:
(i) The ammeter reading (A).
(ii) The electrical energy dissipated by the resistor in one minute.
Date posted: September 10, 2019. Answers (1)
- The figure below shows a diode D connected to a source of a.c current and a resistor.Sketch in the axis below the output observed in...(Solved)
The figure below shows a diode D connected to a source of a.c current and a resistor.
Sketch in the axis below the output observed in the C.R.O.
Date posted: September 10, 2019. Answers (1)
- A heater of resistance R1 is rated P watts, V volts while another of resistance R2 is rated 2P watts, V/2 volts. Determine the ratio...(Solved)
A heater of resistance R1 is rated P watts, V volts while another of resistance R2 is rated 2P watts, V/2 volts. Determine the ratio R1 to R2.
Date posted: September 10, 2019. Answers (1)
- State the name of the eye defect corrected by convex lens.(Solved)
State the name of the eye defect corrected by convex lens.
Date posted: September 10, 2019. Answers (1)
- The figure below shows the path of light through a transparent material placed in air.(Solved)
The figure below shows the path of light through a transparent material placed in air.
Calculate the refractive index of the transparent material.
Date posted: September 10, 2019. Answers (1)