Answer:
The magnetic field due to a solenoid is given as : where, is the permeability of the medium. n is the number of turns or loops in the coil. I is the current flowing in the solenoid.
The magnetic field due to a solenoid can be increased by increasing the number of turns, current and placing an iron core inside the solenoid.
So, the correct option are:
(1) using more wire loops
(2) using a larger current
Hence, the correct options are (a) and (c).
