The magnetic field inside a current-carrying toroidal solenoid is $0.2 \ mT$. What is the magnetic field inside the toroid if the current is tripled (in $mT$)?

$A$ solenoid of $1000$ turns is wound uniformly on a glass tube $4 \text{ m}$ long and $0.3 \text{ m}$ in diameter. The magnetic intensity at the centre of the solenoid when a current of $4 \text{ A}$ flows through it is

$A$ closely wound solenoid $120 \ cm$ long has $4$ layers of windings of $400$ turns each. The diameter of the solenoid is $1.8 \ cm$. If the current carried is $8.0 \ A$,estimate the magnitude of $B$ inside the solenoid near its centre.

"On flowing current in a conducting wire, a magnetic field is produced around it." This is a law of

$A$ solenoid $2 \,m$ long and $4 \,cm$ in diameter has $4$ layers of windings of $1000$ turns each and carries a current of $5 \,A$. What is the magnetic field at its centre along the axis? $\left[\mu_0=4 \pi \times 10^{-7} \,Wb / Am\right]$

$A$ long solenoid with $20$ turns per $cm$ is made. To produce a magnetic field of $20$ $mT$ inside the solenoid, the necessary current will be approximately......$A$.