Advertisements
Advertisements
Question
State two ways to increase the speed of rotation of a D.C. motor.
Advertisements
Solution
By increasing the magnetic flux [by using strong magnet]
By reducing number of turns in the winding.
APPEARS IN
RELATED QUESTIONS
Fill in the following blank with suitable words:
For a current-carrying solenoid, the magnetic field is like that of a ...........
What is the shape of field lines inside a current-carrying solenoid? What does the pattern of field lines inside a current-carrying solenoid indicate?
The diagram given below represents magnetic field caused by a current-carrying conductor which is:
(a) a long straight wire
(b) a circular coil
(c) a solenoid
(d) a short straight wire
What happens when a current-carrying conductor is placed in a magnetic field?
Two coils A and B of insulated wire are kept close to each other. Coil A is connected to a galvanometer while coil B is connected to a battery through a key. What would happen if:
the current is stopped by removing the plug from the key?
Explain your answer mentioning the name of the phenomenon involved.
A flat coil ABCD is freely suspended between the pole pieces of a U-shaped permanent magnet with the plane of coil parallel to the magnetic field.
When will the couple acting on the coil be
- maximum
- minimum?
The following diagram shows two parallel straight conductors carrying the same current. Copy the diagram and draw the pattern of the magnetic field lines around them showing their directions. What is the magnitude of the magnetic field at a point 'X' which is equidistant from the conductors? Give justification for your answer.

State whether a magnetic field is associated or not around a static charge.
A magnetic field directed in north direction acts on an electron moving in east direction. The magnetic force on the electron will act ____________.
For a current in a long straight solenoid N- and S-poles are created at the two ends. Among the following statements, the incorrect statement is
