Magnetic Effects of Electric Current
All about magnetic effects of electric current.
Questions
The strength of a magnetic field is affected by
(a) electric current
(b) number of field lines
(c) direction of field lines
(d) direction of current
- Only a and b
- Only c and d
- Only a, b and c
- Only b, c and d
- All of these
When a piece of soft iron is placed inside a current carrying solenoid, the magnetic field of the electromagnet produced
- disappears in a few seconds
- disappears when the current is turned off
- never disappears
- disappears when the current is increased
- None of these
The magnetic field produced inside a current carrying solenoid is
- straight
- circular
- parabolic
- elliptical
- there is no magnetic field
The pattern formed by the magnetic field at the centre of the loop due to a current through a circular loop is
- dense concentric circles
- scattered concentric circles
- straight line
- random
- None of these
If there are 20 turns in a coil, the magnitude of magnetic field produced by it will be
- 20 + (Magnitude of magnetic field of a single turn of coil)
- 20 - (Magnitude of magnetic field of a single turn of coil)
- 20
- 20 x (Magnitude of magnetic field of a single turn of coil)
- None of these
The three-directional simple rule regarding the current, the magnetic field and the force was given by
- Michael Faraday
- Fleming
- Andre Marie Ampere
- Maxwell
- None of these
Which of the following is incorrect regarding a solenoid?
- Solenoid has many turns
- The wire used in solenoid is of insulated aluminium wire
- Solenoid resembles the shape of a cylinder
- Magnetic materials can be magnetised inside it
- It has two ends North and South pole
According to the right hand thumb rule, the thumb always points towards
- the direction of current flow
- the direction opposite to the current flow
- the direction of the field lines of the magnetic field
- the direction opposite to the field lines of the magnetic field
- the magnetic north pole
If the current flows from East to West, perpendicular to the magnetic field, then in which direction will the Force act on the conductor?
- North
- South
- Parallel to the current flow
- Opposite to the current flow
- None of these
In which of the following devices electric motor is not used as one of the components?
- Washing machine
- Fan
- Refrigerator
- Computer
- LEDs
Match the following:
| 1. | Electric motor | a. | produces DC |
| 2. | Commercial motor | b. | produces AC |
| 3. | Electric generator | c. | split ring commutator |
| 4. | Electrochemical cell | d. | armature |
- 1 - c, 2 - d, 3 - b, 4 - a
- 1 - c, 2 - d, 3 - a, 4 - b
- 1 - d, 2 - c, 3 - b, 4 - a
- 1 - a, 2 - d, 3 - b, 4 - c
- 1 - c, 2 - b, 3 - d, 4 - a
What will be the direction of magnetic field lines around a straight wire, if the direction of current flowing is from south to north?
- South to north
- North to south
- Anti-clockwise
- Clockwise
- None of these
In which of the following directions is the magnetic field lines inside the magnet?
- It is from north to south
- It is from south to north
- It is to and fro
- There are no magnetic field lines inside
- None of these