How is the magnetic field inside a given solenoid made strong?

Hint: In order to solve this question, we should know that a magnetic field is the field produced due to the current carrying conductor and magnets and this magnetic field exerts a magnetic force on current carrying conductors and moving electric charges. Here we will discuss the magnetic field due to the solenoid and then figure out the factors which can increase the strength of the magnetic field in the solenoid.

Complete Step By Step Answer:
Firstly, we should know that In magnetism physics the magnetic field is represented by the letter “B” and its SI unit is tesla denoted by T.
A solenoid is a long cylindrical helix wound coil having a large number of circular turns used to produce the desired magnetic field around it when electric current is passed through it.
Mathematically, if a solenoid has number of turns per unit length of the coil is ‘n’ and current ‘I’ is passed through it, then magnetic field inside the solenoid will be $ B = {\mu _o}nI $ where $ {\mu _o} $ is known as permeability of free space. So, in order to increase magnetic field inside solenoid we can
(a) increase the number of turns per unit length of the coil ‘n’ as $ B \propto n $
(b) increase the electric current I passing through the coil as $ B \propto I $
Hence, these were the main two factors modification which will strengthen the magnetic field inside the solenoid.

Note:
It should be remembered that, the type of material used to make coils of solenoid also affects the magnetic field strength inside the solenoid so generally a laminated iron core is used to increase the efficiency of magnetic field produced in iron core. and the value of $ {\mu _o} = 4\pi \times {10^{ - 7}}Tm{A^{ - 1}} $ is used in its SI units.