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- The figure below shows a method of magnetization used in making magnets.
i)Name the method.
ii) Identify the polarities A and B of the magnet produced.
iii) Apart...(Solved)
The figure below shows a method of magnetization used in making magnets.
i)Name the method.
ii) Identify the polarities A and B of the magnet produced.
iii) Apart from this method, state any other method used in magnetization.
Date posted: October 30, 2019.
- A surface whose work function is 2.46eV is illuminated by light of frequency 3.0×1015Hz. Calculate the maximum kinetic energy of the ejected photoelectrons. (Solved)
A surface whose work function is 2.46eV is illuminated by light of frequency 3.0×1015Hz. Calculate the maximum kinetic energy of the ejected photoelectrons.
Date posted: October 30, 2019.
- The figure below shows a set up that was used to demonstrate the photoelectric effect.
i)If the electroscope was negatively charged, State the observation made.
ii) Explain...(Solved)
The figure below shows a set up that was used to demonstrate the photoelectric effect.
i)If the electroscope was negatively charged, State the observation made.
ii) Explain your answer in (i) above.
iii) State and explain what would happen if the electroscope was positively charged.
Date posted: October 30, 2019.
- The figure below shows the essential components of an x-ray tube
a)Name the parts labelled A and B.
b)Explain how electrons are produced.
c)During the operation of the...(Solved)
The figure below shows the essential components of an x-ray tube
a)Name the parts labelled A and B.
b)Explain how electrons are produced.
c)During the operation of the tube, the target becomes very hot.
i)Explain how this heat is caused.
ii)State any two ways in which cooling can be achieved.
d)Explain why:
i)The tube is evacuated.
ii)The cathode is concave shaped.
Date posted: October 30, 2019.
- A transformer uses 240V a.c supply to deliver 9.0A at 80V to a heating coil. If 10% of the energy taken from the supply is...(Solved)
A transformer uses 240V a.c supply to deliver 9.0A at 80V to a heating coil. If 10% of the energy taken from the supply is lost in the transformer itself, determine the current in the primary winding.
Date posted: October 30, 2019.
- A fishing boat uses ultrasound of frequency 6.0×104Hz to detect fish directly below. Two echoes of the ultrasound are received, one after 0.09 seconds coming...(Solved)
A fishing boat uses ultrasound of frequency 6.0×104Hz to detect fish directly below. Two echoes of the ultrasound are received, one after 0.09 seconds coming from the shoal of fish and the other after 0.12 seconds coming from the sea bed. The sea bed is 84m below the ultrasound transceiver.
i) State two reasons why ultrasound is preferred.
ii) Calculate the speed of the ultrasound waves in water.
Date posted: October 30, 2019.
- The diagram below shows a set up that was used to demonstrate that, sound is a mechanical wave.
i) State the function of the vacuum pump.
ii)...(Solved)
The diagram below shows a set up that was used to demonstrate that, sound is a mechanical wave.
i) State the function of the vacuum pump.
ii) When the switch is closed, state and explain what happens as the air is continuously drawn from the bell jar.
iii)State two possible reasons why it is not possible to reduce the sound completely in this experiment.
Date posted: October 30, 2019.
- Sound is a mechanical longitudinal wave. Explain why sound is classified as;
i)A mechanical wave.
ii)A longitudinal wave.(Solved)
Sound is a mechanical longitudinal wave. Explain why sound is classified as;
i)A mechanical wave.
ii)A longitudinal wave.
Date posted: October 30, 2019.
- A lens forms an image that is four times the size of the object on the screen. The distance between the object and the screen...(Solved)
A lens forms an image that is four times the size of the object on the screen. The distance between the object and the screen is 120cm.
i)State the type of lens used.
ii)Calculate the focal length of the lens.
Date posted: October 30, 2019.
- The figure below shows some of electromagnetic waves in the electromagnetic spectrum.
Arrange them in order of increasing energy contents. (Solved)
The figure below shows some of electromagnetic waves in the electromagnetic spectrum.
Arrange them in order of increasing energy contents.
Date posted: October 30, 2019.
- Diffraction is not a common phenomenon in light. Explain why.(Solved)
Diffraction is not a common phenomenon in light. Explain why.
Date posted: October 30, 2019.
- With the help of a diagram(s) show the difference between half-wave rectification and full-wave rectification output.(Solved)
With the help of a diagram(s) show the difference between half-wave rectification and full-wave rectification output.
Date posted: October 30, 2019.
- The activity of a radioactive source is initially 450 counts per second. After 72 hours, it reduces to 100 counts per second. If the background...(Solved)
The activity of a radioactive source is initially 450 counts per second. After 72 hours, it reduces to 100 counts per second. If the background count per second is 50, determine the half-life of the substance.
Date posted: October 30, 2019.
- The figure below shows a ray of light incident on the surface of one plane mirror.
Sketch the path of the ray on the diagram after...(Solved)
The figure below shows a ray of light incident on the surface of one plane mirror.
Sketch the path of the ray on the diagram after striking mirror 2 indicating all the angles.
Date posted: October 30, 2019.
- A gas container of volume 1.5×10-5m3 contains an ideal gas at a temperature of 270C and pressure 1.0×105 pa. Determine the volume of the gas...(Solved)
A gas container of volume 1.5×10-5m3 contains an ideal gas at a temperature of 270C and pressure 1.0×105 pa. Determine the volume of the gas when cooled to 170C and its pressure raised to 1.5×105 pa.
Date posted: October 30, 2019.
- In an experiment to determine the specific latent heat of vaporization of water, steam at 1000C was passed into water contained in a well lagged...(Solved)
In an experiment to determine the specific latent heat of vaporization of water, steam at 1000C was passed into water contained in a well lagged copper calorimeter. The following measurements were made:
- Mass of calorimeter = 55g
- Initial mass of water = 75g
-Final mass of calorimeter + water + condensed steam = 133g
- Final temperature of the mixture = 300C.
Specific heat capacity of water = 4200J/Kg/K.
Specific heat capacity of copper = 390J/Kg/K.
Determine the:
i)Mass of condensed steam
ii)Heat gained by the calorimeter and water if the initial temperature of the calorimeter
+ water = 200C
iii)Given that L is the specific latent heat of vaporization of steam.
(I)Write an expression for the heat given out by steam.
(II)Determine the value of L.
Date posted: October 30, 2019.
- The figure below shows a simple machine being used to raise a load W by applying an effort E.
i)Name the machine.
ii)Show that the velocity...(Solved)
The figure below shows a simple machine being used to raise a load W by applying an effort E.
i)Name the machine.
ii)Show that the velocity ratio (V.R) of the machine is given by R/r
iii)Given that r =11cm and R = 99cm, determine the effort E required to raise a load of 2800N
if the efficiency of the machine is 95%.
Date posted: October 30, 2019.
- Figure below shows dots which were made by a ticker timer tape attached to a trolley.
If the frequency used was 50Hz, determine;
a)The velocities between AB...(Solved)
Figure below shows dots which were made by a ticker timer tape attached to a trolley.
If the frequency used was 50Hz, determine;
a)The velocities between AB and BC.
b)The deceleration of the trolley.
Date posted: October 30, 2019.
- Figure below shows a uniform metre rule balancing when a mass of 200g is hung at one end.
Determine the tension T in the string. (Solved)
Figure below shows a uniform metre rule balancing when a mass of 200g is hung at one end.
Determine the tension T in the string.
Date posted: October 30, 2019.
- A person of mass 70kg stands on a scale balance in a lift. At a particular instant the lift is moving downward uniformly at 2.8m/s2....(Solved)
A person of mass 70kg stands on a scale balance in a lift. At a particular instant the lift is moving downward uniformly at 2.8m/s2. Calculate the reading on the scale in Newtons.
Date posted: October 30, 2019.
- The figure below shows a displacement time graph.
Describe the motion of the body between points:
OA
AB(Solved)
The figure below shows a displacement time graph.
Describe the motion of the body between points:
OA
AB
Date posted: October 30, 2019.
- The figure below shows a measuring cylinder which contains water initially at a level A.
A spherical solid is immersed in the water and the level...(Solved)
The figure below shows a measuring cylinder which contains water initially at a level A.
A spherical solid is immersed in the water and the level rises to B.
Determine the diameter of the spherical ball.
Date posted: October 30, 2019.
- In the figure below OAB is a triangle in which OS =3/4 OA and AR:RB = 2:1 Lines OR and SB meet at T.
a)Given that...(Solved)
In the figure below OAB is a triangle in which OS =3/4 OA and AR:RB = 2:1 Lines OR and SB meet at T.
a)Given that OA =a and OB =b, express in terms of a and b
i)AB
ii)OR
iii)SB
b)Given that ST=mSB and OT=nOR, determine the values of the scalars m and n
Date posted: October 30, 2019.
- Three quantities P, Q and R are such that P varies directly as the square of Q and inversely as the square root of R.
a)Given...(Solved)
Three quantities P, Q and R are such that P varies directly as the square of Q and inversely as the square root of R.
a)Given that P = 20 when Q = 5 and R = 9. Find P when Q = 7 and R = 25
b)If Q increased by 20% and R decreased by 36%, find the percentage change in P
Date posted: October 30, 2019.
- a)Two blends of tea costing Ksh. 140 and Ksh.160 per kg respectively are mixed in the ratio 2:3 by mass. The mixture is sold at...(Solved)
a)Two blends of tea costing Ksh. 140 and Ksh.160 per kg respectively are mixed in the ratio 2:3 by mass. The mixture is sold at sh.240 per kg.
i)Find the percentage profit
ii)In what ratio should the two blends be mixed to get a mixture that costs sh.148 per kg
b)A quantity P is partly constant and partly varies as the cube of Q. when Q = 2, P = 50 and when Q =4, P =330. Find the value of Q when P= 16885
Date posted: October 30, 2019.
- Complete the table below for the curves y =3cos2x and y = 2sin(2x + 30)0
(Solved)
Complete the table below for the curves y =3cos2x and y = 2sin(2x + 30)0
Date posted: October 30, 2019.
- An aircraft leaves town P(300S,140W) and moves directly east to town Q at a speed of 270 knots for 12 hours. Determine;
a)The distance moved in...(Solved)
An aircraft leaves town P(300S,140W) and moves directly east to town Q at a speed of 270 knots for 12 hours. Determine;
a)The distance moved in nautical miles
b)The distance moved in km (take 1nm = 1.853km)
c)The position of town Q
d)The local time at Q if the local time at P is 9.13pm. Give the answer to the nearest minute.
Date posted: October 30, 2019.
- The table below shows the ages in years of 60 candidates who vied on a political party for parliamentary elections in a certain country as...(Solved)
The table below shows the ages in years of 60 candidates who vied on a political party for parliamentary elections in a certain country as recorded in a computer program.
Calculate;
a)The mean
b)The interquartile range of the data
c)The percentage of candidates whose ages were 54.5 years and below
d)The variance and standard deviation of the distribution using 44.5 as the working mean.
Date posted: October 30, 2019.
- The major arc of a circle subtends on an angle of 2400 at the centre of circle. Given that the, length of the arc is...(Solved)
The major arc of a circle subtends on an angle of 2400 at the centre of circle. Given that the, length of the arc is 88cm calculate the diameter of the circle.
Date posted: October 30, 2019.
- Find the radius and centre of a circle whose equation is
2x2 + 2y2 - 16x + 8y +8 =0 (Solved)
Find the radius and centre of a circle whose equation is
2x2 + 2y2 - 16x + 8y +8 =0
Date posted: October 30, 2019.