Advertisements
Advertisements
प्रश्न
State the function of a split ring in D.C. motor.
Advertisements
उत्तर
When the coil of a D. C motor turns through 180°, the split ring reverses the direction of the current in the coil from CBAD to DABC.
In this way, the coil continues to rotate continuously in the same direction and positive and negative polarities are maintained.
संबंधित प्रश्न
Show with the aid of a diagram how a wire is wound on a U-shaped piece of soft iron in order to make it an electromagnet. Complete the circuit diagram and label the poles of the electromagnet.
Fill in the blanks by writing (i) Only soft iron, (ii) Only steel, (iii) Both soft-iron and steel for the material of core and/or magnet.
Electromagnet ______.
Complete the following sentence :
On reserving the direction of current in a wire, the magnetic field produced by it gets _____.
The magnetic flux through a coil having 100 turns decreases from 5 milli weber to zero in 5 second. Calculate the e.m.f. induced in the coil.
Answer the following in short.
Name a few common appliances that use electromagnets.
What will be the effect on the working of an electric bell if instead of a direct current an alternating current is used?
The primary windings of a step-up transformer are usually made of thicker wire than the secondary. Explain.
State important properties (or characteristics) of magnetic lines of force around a straight conductor.
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.
