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1. Energy loss due to friction between brushes and commutators.
2. Resistance of the coil
3. Energy loss due to heat during magnetization and demagnetization
4. Flux leakage
Wilfykil answered the question on March 26, 2019 at 05:32
- Figure below shows a D.C electric motor.(Solved)
Figure below shows a D.C electric motor.
(a) Name the parts labeled X1 and X2 and state their functions.
(b) What is the purpose of parts labeled Y1 and Y2?
(c) When the switch k is closed state the forces acting on the sides of the coil and the direction of movement of the coil
(d) What can be done to increase the speed of rotation of the motor?
Date posted: March 26, 2019. Answers (1)
- An un-insulated copper wire XY lies over the fixed wire A and B connected to a battery when the key in the circuit is closed,...(Solved)
An un-insulated copper wire XY lies over the fixed wire A and B connected to a battery when the key in the circuit is closed, the wire XY experiences a force.
(i) In which direction does the wire XY- experience the force?
(ii) How do you determine the direction in (i) above
(iii) When is the force on the wire XY greatest?
(iv) What is the effect of reversing both the magnetic field and direction of flow of current?
(v) State TWO factors by which the force on XY can be decreased
Date posted: March 26, 2019. Answers (1)
- An iron rod XY is placed inside a coil of wire. What type of magnetic pole is induced at the end x when the current...(Solved)
An iron rod XY is placed inside a coil of wire. What type of magnetic pole is induced at the end x when the current flows through the coil?
Date posted: March 26, 2019. Answers (1)
- Figure below shows an incomplete circuit of an electromagnet. Complete the circuit between X and Y by drawing the windings on the two arms of...(Solved)
Figure below shows an incomplete circuit of an electromagnet. Complete the circuit between X and Y by drawing the windings on the two arms of the core such that A and B are both North poles when switch S is closed. Indicate the direction of the current on the windings drawn.
Date posted: March 26, 2019. Answers (1)
- An armature composed of turns of insulated copper wire wound on a laminated soft- iron core is rotated in a magnetic field to generate an...(Solved)
An armature composed of turns of insulated copper wire wound on a laminated soft- iron core is rotated in a magnetic field to generate an e.m.f. Use this information to answer the following questions.
(a) State two factors other than the speed of rotation that affect the magnitude of the e.m.f generated.
(b) State the reason why soft- iron is laminated.
Date posted: March 26, 2019. Answers (1)
- Figure below shows an electric generator. The points P and Q are connected to a Cathode Ray Oscilloscope (CRO).(Solved)
Figure below shows an electric generator. The points P and Q are connected to a Cathode Ray Oscilloscope (CRO).
Sketch on the axes provided the graph of the voltage output as seen on the CRO, given that when t= 0, the coil is at the position shown in the figure.
Date posted: March 26, 2019. Answers (1)
- State characteristics of an image observed in a concave mirror when the object is between the focal point and the mirror.(Solved)
State characteristics of an image observed in a concave mirror when the object is between the focal point and the mirror.
Date posted: March 26, 2019. Answers (1)
- Figure below shows the reading on a burette after 55 drops of a liquid have been used. If the initial reading was at zero mark,...(Solved)
Figure below shows the reading on a burette after 55 drops of a liquid have been used. If the initial reading was at zero mark, determine the volume of one drop.
Date posted: March 25, 2019. Answers (1)
- A small object is placed 30cm away from a diverging lens of focal length 10cm. Determine by scale drawing the position and nature of image...(Solved)
A small object is placed 30cm away from a diverging lens of focal length 10cm. Determine by scale drawing the position and nature of image formed.
Date posted: March 25, 2019. Answers (1)
- Name the part of the eye which changes the focal length of the eye.(Solved)
Name the part of the eye which changes the focal length of the eye.
Date posted: March 25, 2019. Answers (1)
- A wire placed between the poles of two permanent magnets is connected to a galvanometer as shown below.(Solved)
A wire placed between the poles of two permanent magnets is connected to a galvanometer as shown below.
a)State what is observed when the wire is moved up and down.
c) Suggest two ways of increasing the magnitude of the effect you have stated in (a) above.
Date posted: March 25, 2019. Answers (1)
- The figure below shows a P - N junction.(Solved)
The figure below shows a P - N junction.
Complete the diagram so that the function is reverse biased.
Date posted: March 25, 2019. Answers (1)
- Fig 6 (a) and (b) shows a convex mirror and a plane mirror of equal aperture(Solved)
Fig 6 (a) and (b) shows a convex mirror and a plane mirror of equal aperture
By sketching a pair of incident and reflected rays for each (a) and (b) shows how the convex mirror provides to the eye, a wide field of new than the plane mirror.
Date posted: March 25, 2019. Answers (1)
- The graph in the figure below shows a forward bias characteristics of a P-N junction.(Solved)
The graph in the figure below shows a forward bias characteristics of a P-N junction.
The depletion layer decreases from O to A. Explain what is meant by depletion layer.
Date posted: March 25, 2019. Answers (1)
- The figure below shows two parallel rays incident on a concave mirror. F is the focal point of the mirror.(Solved)
The figure below shows two parallel rays incident on a concave mirror. F is the focal point of the mirror.
On the same diagram sketch the path of the rays after striking the mirror
Date posted: March 25, 2019. Answers (1)
- Distinguish between intrinsic and extrinsic semi-conductors.(Solved)
Distinguish between intrinsic and extrinsic semi-conductors.
Date posted: March 25, 2019. Answers (1)
- A doctor suspects that one of the kidneys of a patient is not working properly. The doctor injects him with a radioactive impurity, 1MBq of...(Solved)
A doctor suspects that one of the kidneys of a patient is not working properly. The doctor injects him with a radioactive impurity, 1MBq of iodine-131 (half-life 8 days) which travels to his kidneys. A normal kidney gradually removes all impurity from the blood in about 20 minutes. The radioactivity in his kidney is monitored. using gamma ray detectors. The graph below shows the results.
a) Which kidney do you think is not working properly? Explain your answer.
b) Why do you think that a gamma ray emitter was used as the injected impurity instead of a beta emitter?
c) Why would it be less suitable to use as an impurity a material with a very short half-life?
Date posted: March 25, 2019. Answers (1)
- State the modification introduced in the modern buses so as to enhance stability(Solved)
State the modification introduced in the modern buses so as to enhance stability
Date posted: March 25, 2019. Answers (1)
- State the necessary conditions for equilibrium of body which is acted upon by a number of forces(Solved)
State the necessary conditions for equilibrium of body which is acted upon by a number of forces
Date posted: March 25, 2019. Answers (1)
- State two factors that determine the stability of a vehicle(Solved)
State two factors that determine the stability of a vehicle
Date posted: March 25, 2019. Answers (1)