Electromagnets
Trending Questions
Name the material used for preparing an electromagnet.
- T.V.
- Electric Bell
- Electric Heater
- Radio
Electromagnets are permanent magnets.
Say True or False.
True
False
Branch of physics which deals with magnetic effects of electric current is called:-
Magnetism
Electromagnetism
Electrostatics
Electromagnetic induction
Choose the correct statements from the below mentioned statements:-
Electromagnets are made of soft iron while permanent magnets are made of steel.
Polarity of an electromagnet can be reversed but polarity of permanent magnet cannot be reversed.
Magnetic field of electromagnet is weak while magnetic field of permanent magnet is very strong
Electromagnet cannot be easily demagnetised while permanent magnet can be easily demagnetised.
When magnetic field lines are closer, the magnetic field is ___.
weaker
stronger
random
non-existent
Electromangets are made up of :
(a) steel (b) copper
(c) soft iron (d) aluminium
The strength of the electromagnet can be increased by
(a) reversing the directions of current
(b) using an alternating current of high frequency
(c) increasing the current in the coil
(d) decreasing the number of turns of coil.
Electromagnetism is a branch of physics which deals with electricity.
- True
- False
A coil of insulated copper wire is wound around a piece of soft iron and current is passed in the coil from a battery. What name is given to the device so obtained ? Give one use of the device mentioned by you.
The branch of physics which deals with the magnetic effect of the electric current is called as
Electrophysics
Electric physics
Electromagnetism
None of these
Why is soft iron used as the core of the elctromagnet in an electric bell ?
- Magnetic effect
- Heating effect
- Chemical Effect
Fig. 10.18 shows a coil wound around a soft iron bar XY. (a) State the polarity at the ends X and Y as the switch is pressed. (b) Suggest one way of increasing the strength of electromagnet so formed.
Upon which of the following effects are the electromagnets based?
Magnetic effect of electric current
Chemical effect of electric current
Electro-chemical effect of electric current
Heating effect of electric current
- The magnetic property is caused due to the flowing current.
- Poles can be interchanged.
- Electromagnets are temporary magnets.
- The magnetic strength cannot be changed.
- The direction of the magnetic field is tangent to the field line at any point in space.
- Magnetic field lines represent zero field strength if they are parallel and equidistant.
- Magnetic field lines are closed curves.
- The degree of closeness of the field lines at a point is the relative strength of magnetic field strength at that point.
Suppose we have a solenoid with two ends A and B. If current at face A is clockwise while at B is anticlockwise. So, A and B act as:-
A as north pole and B as south pole
B as north pole and A as south pole
Both A and B as north pole
Both A and B as south pole
Working of an electromagnet is based on ___.
Heating effect of electric current
Electro-chemical effect of electric current
Magnetic effect of electric current
Chemical effect of electric current
What is an electromagnet
Electromagnets are permanent magnets.
True
False
- True
- False
A crane uses a mysterious object ‘X’ to separate magnetic materials from junk. The object ‘X’ is most probably
Electromagnet
Permanent magnet
Magnetic material
None of the above
- The needle is fixed too tight
- Magnetic field lines have a single direction
- Magnetic field of the magnet doesn’t influence the point
- The compass is malfunctional
Which among the following works on the basis of magnetic effect of electric current?
Electromagnet
Electric heater
Electric fuse
Electric press
Study the statements given below:
(i) Electromagnets can be made more powerful than ordinary bar magnets.
(ii) Soft iron is easy to magnetize and demagnetize.
(iii) The poles of an electromagnet are not affected by the direction of the current.
Which of the above statements about the electromagnets are correct?
Only (i) and (ii)
Only (ii) and (iii)
(i), (ii) and (iii)
Only (i) and (iii)
- None of the above
- North pole to south pole
- South pole to north pole
- They don't exist inside the magnet