Physics
Which of the following statements is not true for an electromagnet ?
- It is made of soft iron.
- Its magnetic field strength can be changed.
- The polarity of an electromagnet cannot be changed.
- It can easily be demagnetised.
Related Questions
In the figure given below, the direction of current in the loop is …………… . So, it behaves as a …………… .
- anticlockwise, south pole
- anticlockwise, north pole
- clockwise, north pole
- clockwise, south pole
Which of the following statements is not true ?
- The strength of magnetic field due to a bar magnet can be changed.
- A solenoid behaves like a bar magnet i.e. it attracts iron filings.
- The magnetic field increases if a soft iron core is placed along the axis of solenoid.
- The magnetic field lines inside the solenoid are nearly straight and parallel to the axis of solenoid.
The magnetic field lines inside a solenoid are :
- parallel and circular
- straight and parallel to the axis of solenoid
- straight and perpendicular to the axis of solenoid
- circular
On reversing the direction of current in a wire, the magnetic field produced by it:
- gets reversed in direction
- increases in strength
- decreases in strength
- remains unchanged in strength and direction.