Solenoid and Toroid

The magnetic field inside a long solenoid is

When the number of turns in a toroidal coil is doubled, then the value of magnetic flux density will become,

A short solenoid (length $l$ and radius $r$ with $n$ turns per unit length) lies well inside and on the axis of a very long, coaxial solenoid (length $L$, radius $R$ and $N$ turns per unit length, with $R>r$). Current $I$ follows in the short solenoid. Choose the correct statement.

Two current-carrying solenoids exhibit: 

A solenoid of length 1.0m has a radius of 1cm and has a total of 1000 turns wound on it. It carries a current of 5A. If an electron were to move with a speed of ${10}^4 m{s}^{-1}$ along the axis of this current carrying solenoid the force experienced by this electron is

A toroid of mean radius 'a' , cross section radius 'r' and total number of tums N. lt carries a current 'i'. The torque experienced by the toroid if a uniform magnetic field of strength B is applied:

A wire is wound on a long rod of material of relative permeability ${\mu }_{\text{r}}=4000$ to make a solenoid. If the current through the wire is 5 A and number of turns per unit length is 1000 per metre, then the magnetic field inside the solenoid is :

When $100 \mathrm{V}$ DC is applied across a solenoid a current of $1 \mathrm{A}$ flows in it. When $100 \mathrm{V}$ AC is applied across the same coil, the current drops to $0.5 \mathrm{A}$. The frequency of the AC is $50 \mathrm{Hz}$. The impedance and inductance of the solenoid are

A solenoid of 1.5 m length and 4.0 cm diameter has 10 turns per cm. A current of 5 A is flowing through it. The magnetic field induction at axis inside the solenoid is

A closely wound solenoid of $800$ turns and area of cross-section $2.5\times {10}^{-\mathrm{4 }}\mathrm{}{\mathrm{m}}^2$ carries a current of $3.0 \mathrm{A}$ . What is its associated magnetic moment?

A current carrying circular coil is bent so as to convert it into a double loop, both the loops being concentric and are carrying current in the same direction. If $\mathrm{B}$ is the initial magnetic field at the centre, the final magnetic field at the centre will be