Advertisements
Advertisements
Question
principle of an electric motor ?
Advertisements
Solution
Principle: An electric motor (dc motor) works on the principle that when an electric current is passed through a conductor placed normally in a magnetic field, a force acts on the conductor as a result of which the conductor begins to move and mechanical energy is obtained.
RELATED QUESTIONS
Suppose you are given a long bar magnet and you are asked to break it into four small magnets. Draw diagrams showing the polarities of each broken part.
State two factors on which the strength of induced e. m.f. depends.
What energy conversion takes place during the working of a d c motor?
State the position of armature coil relative to the direction of magnetic field, in a D. C. motor when the deflecting couple acting an the coil is maximum.
The primary windings of a step-up transformer are usually made of thicker wire than the secondary. Explain.
What are the factors that govern the magnitude of force acting on a current carrying conductor which is freely suspended in a magnetic field?
Point out three differences between an electromagnet and a bar (or permanent) magnet.
(i) A straight wire conductor passes vertically through a piece of cardboard sprinkled with iron filings. Copy the diagram and show the setting of iron filings when a current is passed through the wire in the upward direction and the cardboard is tapped gently. Draw arrows to represent the direction of the magnetic field lines.
(ii) Name the law which helped you to find the direction of the magnetic field lines.
How does a magnetic field set up by a solenoid change when cross-sectional area of solenoid is increased?
Which magnet will you use?
Iron is to be separated from trash.
