-
A Power station has an input of 30kw at a potential difference of 5kv.A transformer with a secondary coil of 1000 turns is used to...
(Solved)
A Power station has an input of 30kw at a potential difference of 5kv.A transformer with a secondary coil of 1000 turns is used to step down the voltage to 1000v for transmission along a grid .Assuming there are no power loses in the transformer .calculate.
i) current in the primary coil
ii) The number of turns in the primary coil
iii) The current in the secondary coil
iv) State which of the coils is thick and why
Date posted:
May 31, 2019
.
Answers (1)
-
The graph below shows the relationship between the voltage drop across a certain capacitor and the charge stored in the capacitor.
From the graph calculate the...
(Solved)
The graph below shows the relationship between the voltage drop across a certain capacitor and the charge stored in the capacitor.
From the graph calculate the capacitance of the capacitor.
Date posted:
May 31, 2019
.
Answers (1)
-
The diagram below shows a circuit containing three capacitors.
i) Write an expression for effective capacitance between X and Y.
ii) If c1=6µF, c2=4.5µF and c3=5 µF,...
(Solved)
The diagram below shows a circuit containing three capacitors.
i) Write an expression for effective capacitance between X and Y.
ii) If c1=6μF, c2=4.5μF and c3=5 μF, calculate the charge stored when point XY is connected in series with a battery of 6V
Date posted:
May 31, 2019
.
Answers (1)
-
Show the charge distribution on the hollow conductor shown below if it is positively charged.
(Solved)
Show the charge distribution on the hollow conductor shown below if it is positively charged.
Date posted:
May 31, 2019
.
Answers (1)
-
A charge of 4.8C flows through a lamp every second. Calculate the number of electrons involved per second.
(Solved)
A charge of 4.8C flows through a lamp every second. Calculate the number of electrons involved per second.
Date posted:
May 31, 2019
.
Answers (1)
-
The figure below shows a ray of light incident on a water-air interface from a source 8m deep.
i) Ray A is observed to bend as...
(Solved)
The figure below shows a ray of light incident on a water-air interface from a source 8m deep.
i) Ray A is observed to bend as it enters the air. Give a reason why this occurs
ii) If the refractive index of water is 1.35, calculate the angle of refraction of ray A
iii) Find the critical angle of water
iv) Give a reason why ray B is not travelling out of water
v) A fish is placed at the source of light ray. Calculate the maximum area of view on the surface of water
Date posted:
May 31, 2019
.
Answers (1)
-
The figure below shows a simple electric motor. Study the figure and answer the questions that follow.
i) Indicate on the diagram the direction of rotation...
(Solved)
The figure below shows a simple electric motor. Study the figure and answer the questions that follow.
i) Indicate on the diagram the direction of rotation of the coil.
ii) Explain how the motor works specifying clearly the functions of the parts P and Q.
iii) State one way by which the speed of this motor can be increased.
Date posted:
May 31, 2019
.
Answers (1)
-
The graph in the figure below shows variation in activity of a sample of a radioactive material.
Use the graph to determine the half life of...
(Solved)
The graph in the figure below shows variation in activity of a sample of a radioactive material.
Use the graph to determine the half life of the sample
Date posted:
May 31, 2019
.
Answers (1)
-
A photo sensitive cathode of work function 2.1 eV is illustrated with a radiation of wavelength 4.5× 10-7. Determine the stopping potential for the cathode....
(Solved)
A photo sensitive cathode of work function 2.1 eV is illustrated with a radiation of wavelength 4.5× 10-7. Determine the stopping potential for the cathode. Speed of light C = 3.0 × 108m/s,1 eV = 1.6 × 10-19j,
h = 6.6 × 10-34Js.
Date posted:
May 31, 2019
.
Answers (1)
-
The figure shows an apparatus used to investigate photoelectric effect.
i) Name the parts A and B.
ii) State the function of C.
(Solved)
The figure shows an apparatus used to investigate photoelectric effect.
i) Name the parts A and B.
ii) State the function of C.
Date posted:
May 31, 2019
.
Answers (1)
-
The figure shows a loudspeaker producing sound waves in air.
i) Explain how compression and rarefactions are formed.
iii) The wavelength of the waves produced is...
(Solved)
The figure shows a loudspeaker producing sound waves in air.
i) Explain how compression and rarefactions are formed.
iii) The wavelength of the waves produced is 0.4m. Determine the frequency of the waves if the speed of sound in air is 330m/s.
Date posted:
May 31, 2019
.
Answers (1)
-
A radio transmitter produces waves of frequency 1.5×108Hz. Determine the wavelength of the signal (C = 3.0 × 108m/s).
(Solved)
A radio transmitter produces waves of frequency 1.5×108Hz. Determine the wavelength of the signal (C = 3.0 × 108m/s).
Date posted:
May 31, 2019
.
Answers (1)
-
The figure below shows a graph of values of reciprocal of frequency and corresponding values of wavelength for waves transmitted in a certain medium.
i) Using...
(Solved)
The figure below shows a graph of values of reciprocal of frequency and corresponding values of wavelength for waves transmitted in a certain medium.
i) Using the wave equation, give the equation of the graph.
ii) Use the graph to determine the velocity of the waves.
Date posted:
May 31, 2019
.
Answers (1)
-
The figure below shows a coil connected to a sensitive galvanometer.
When the magnet is suddenly moved towards the coil in the direction shown, the galvanometer...
(Solved)
The figure below shows a coil connected to a sensitive galvanometer.
When the magnet is suddenly moved towards the coil in the direction shown, the galvanometer shows a deflection.Explain.
Date posted:
May 31, 2019
.
Answers (1)
-
Name an electromagnetic radiation with highest energy photons.
(Solved)
Name an electromagnetic radiation with highest energy photons.
Date posted:
May 31, 2019
.
Answers (1)
-
An electric heater is rated 1kW, 240V. If the element is connected to 240V mains supply for 10 minutes, determine the amount of heat dissipated.
(Solved)
An electric heater is rated 1kW, 240V. If the element is connected to 240V mains supply for 10 minutes, determine the amount of heat dissipated.
Date posted:
May 31, 2019
.
Answers (1)
-
The figure below shows a circuit diagram. The emf of the cell is 1.5V. When the switch is closed, the voltmeter reads 1.3V and the
ammeter...
(Solved)
The figure below shows a circuit diagram. The emf of the cell is 1.5V. When the switch is closed, the voltmeter reads 1.3V and the
ammeter reads 0.8A.
Determine the internal resistance of the cell.
Date posted:
May 31, 2019
.
Answers (1)
-
The figure shows a ray of light travelling through a vacuum enters liquid X at an angle of 50°, travels through and emerges in
glass.
Determine angle...
(Solved)
The figure shows a ray of light travelling through a vacuum enters liquid X at an angle of 50°, travels through and emerges in
glass.
Determine angle Y.
Date posted:
May 31, 2019
.
Answers (1)
-
Identify the magnetic poles A, B, C and D in the diagram below.
(Solved)
Identify the magnetic poles A, B, C and D in the diagram below.
Date posted:
May 31, 2019
.
Answers (1)
-
A person claps his hands at approximately 0.5s intervals in front of a wall 90m away. He notices that each echo produced by the wall...
(Solved)
A person claps his hands at approximately 0.5s intervals in front of a wall 90m away. He notices that each echo produced by the wall coincides with the next clap.
i) Calculate the approximate speed of sound
ii) If the results obtained above were used as a basis for an experimental method to determine the speed of sound, what procedure should be adopted to obtain high accuracy in the timing part of the experiment?
Date posted:
May 31, 2019
.
Answers (1)