- 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.
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.
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.
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.
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.
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.
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.
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.
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.
Draw the waves after passing section B.
Date posted: October 17, 2019. Answers (1)