what is the factor on which magnitude of  magnetic field depends?

The magnitude of magnetic field at a point due to a straight current carrying wire depends upon:

1. The current passing through the wire - directly proportional, greater the current in wire , stronger will be the magnetic field produced.
2. The distance of that point from the wire- inversely proportional,greater the distance of the point from the current carrying wire, weaker will be the magnetic field produced at that point.

The magnitude of magnetic field produced by a current carrying circular loop depends upon:

1. The current passing through the circular loop-directly proportional.
2. The radius of circular loop-inversely proportional
3. Number of turns of the wire in the circular loop-directly proportional.

The magnitude of magnetic field produced by a current carrying solenoid depends upon:

1. The number of turns in the solenoid-Larger the number of turns in the solenoid, greater will be the magnetism produced.
2. The strength of current in the solenoid-Larger the current passed through the solenoid, stronger will be the magnetic field.
3. The nature of core material in making solenoid-Use of soft iron rod as core in a solenoid produces the strongest magnetism.