1.Explain magnetic field due to current …

• Magnetic Field due to a Current carrying Conductor:

Magnetic Field due to a Straight Current-carrying Conductor:

The magnetic field lines around a straight conductor carrying a current are concentric circles.

The direction of a magnetic field is given by the Right-Hand Thumb Rule.

Right-Hand Thumb Rule:

Imagine that you are holding a straight current-carrying conductor in your right hand such that the thumb points towards the direction of the current. Then, your curved fingers wrapped around the conductor point in the direction of the field lines of the magnetic field.

The magnitude of the magnetic field due to a straight current-carrying conductor at a given point is

1. Directly proportional to the current flowing through the conductor.
2. Inversely proportional to the distance of that point from the conductor.

Magnetic Field due to a Current-carrying Circular Coil:

1. The magnetic field lines near the coil are nearly circular or concentric.
2. The magnetic field at the centre of the coil is maximum and almost uniform.
3. Looking at the face of a coil, if the current around it is in the clockwise direction, then it faces the South Pole. If the current around it is in the anticlockwise direction, then it faces the North Pole. This is called the Clock rule.
4. The magnitude of a magnetic field at the centre of the coil is

1. Directly proportional to the current flowing through it
2. Inversely proportional to the radius of the coil
3. Directly proportional to the number of turns of the coil

Magnetic Field due to a Current-carrying Solenoid:

Solenoid is a long coil containing a large number of close turns of insulated copper wire. The magnetic field produced by passing the current through the coil. Magnetic field produced by the solenoid is similar to the magnetic field produced by the bar magnet. The magnetic field lines in the solenoid are parallel.

The magnetic field inside a solenoid is uniform.

In  accordance  with  the Clock  rule,  the  end  of  the  solenoid  at  which  the  current  flows in  the anticlockwise direction behaves  as  a North Pole,  while  the  end  at  which  the  current  flows in  the clockwise direction behaves as a South Pole.

The magnitude of the magnetic field inside the solenoid is directly proportional to the

1. Current flowing through it
2. Number of turns per unit length of the solenoid