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- 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. Answers (1)
- 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.
![fig47301020191332.png](/questions/uploads/fig47301020191332.png)
Sketch the path of the ray on the diagram after striking mirror 2 indicating all the angles.
Date posted: October 30, 2019. Answers (1)
- 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. Answers (1)
- 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. Answers (1)
- 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.
![fig43301020191234.png](/questions/uploads/fig43301020191234.png)
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. Answers (1)
- 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.
![fig40301020191213.png](/questions/uploads/fig40301020191213.png)
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. Answers (1)
- 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.
![fig38301020191206.png](/questions/uploads/fig38301020191206.png)
Date posted: October 30, 2019. Answers (1)
- 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. Answers (1)
- 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.
![fig37301020191146.png](/questions/uploads/fig37301020191146.png)
Describe the motion of the body between points:
OA
AB
Date posted: October 30, 2019. Answers (1)
- 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.
![fig35301020191141.png](/questions/uploads/fig35301020191141.png)
Determine the diameter of the spherical ball.
Date posted: October 30, 2019. Answers (1)
- Explain why a porridge in a cup wrapped with a wet cloth cools faster than when the cup is dipped in cold water.(Solved)
Explain why a porridge in a cup wrapped with a wet cloth cools faster than when the cup is dipped in cold water.
Date posted: October 28, 2019. Answers (1)
- i)Why should argon gas be at low pressure in a Geiger–Muller tube?
ii)State the purpose of the bromine gas in the tube.(Solved)
i)Why should argon gas be at low pressure in a Geiger–Muller tube?
ii)State the purpose of the bromine gas in the tube.
Date posted: October 17, 2019. Answers (1)
- Sodium has work function of 2.42eV. Calculate its threshold frequency.
(Take the plank’s constant to be 6.6 x 10-34 J)
(Solved)
Sodium has work function of 2.42eV. Calculate its threshold frequency.
(Take the plank’s constant to be 6.6 x 10-34 J)
Date posted: October 17, 2019. Answers (1)
- i)Sketch on the axis below a graph of the e.m.f generated against the angle as the coil rotates from 00 to 900 and from 900...(Solved)
i)Sketch on the axis below a graph of the e.m.f generated against the angle as the coil rotates from 00 to 900 and from 900 to 1800.
![fig42171020191419.png](/questions/uploads/fig42171020191419.png)
ii)Give reasons for the changes in the e.m.f as the coil rotates from 00 to 1800.
Date posted: October 17, 2019. Answers (1)
- How is flux leakage minimized?(Solved)
How is flux leakage minimized?
Date posted: October 17, 2019. Answers (1)
- Define flux leakage as used in transformers.(Solved)
Define flux leakage as used in transformers.
Date posted: October 17, 2019. Answers (1)
- The diagram below is a circuit with 2 bulbs and components D.
State and explain which of the lamps L1 and L2 would light when the...(Solved)
The diagram below is a circuit with 2 bulbs and components D.
![fig41171020191410.png](/questions/uploads/fig41171020191410.png)
State and explain which of the lamps L1 and L2 would light when the switch is closed.
Date posted: October 17, 2019. Answers (1)
- A tube of length 36cm is closed at one end. It is at resonance with a turning fork of frequency 256Hz sounded above the open...(Solved)
A tube of length 36cm is closed at one end. It is at resonance with a turning fork of frequency 256Hz sounded above the open end. Given that the velocity of sound in air is 334m/s.
Determine:
i)The wavelength of the wave generated by the turning fork.
ii)The end correction of the tube.
Date posted: October 17, 2019. Answers (1)
- State two conditions necessary for production of constructive interference. (Solved)
State two conditions necessary for production of constructive interference.
Date posted: October 17, 2019. Answers (1)
- The figure below shows plane waves in a ripple tank. The water is deeper in section A and C then in section B.
Draw the waves...(Solved)
The figure below shows plane waves in a ripple tank. The water is deeper in section A and C then in section B.
![fig38171020191358.png](/questions/uploads/fig38171020191358.png)
Draw the waves after passing section B.
Date posted: October 17, 2019. Answers (1)