 # Explain faraday experiment in details

Changes in flux linked with a loop is induces emf in the loop.

Magnitude of the emf induced is directly proportional to the rate of change of flux linked with the loop.

$e=frac{-dphi }{dt}$

We know $phi$ = flux linked with the loop.

Faraday used a galvanometer, a conducting loop and a bar magnet.

Galvanometer is connected to the conducting loop.

Case: I

There is no deflection in the galvanometer when there is no relative motion between the conducting loop and bar magnet.

Case: II

There is a deflection in the galvanometer, when there is a relative motion between conducting loop and bar magnet. And he observed difference in direction of deflection.

$left. begin{matrix} when,barmagnet,approaches \ the,conducting,loop \ end{matrix} right}Rightarrow begin{matrix} galvanometer,deflection,is \ ioperatorname{s},,in,one,direction \ end{matrix}$ $left. begin{matrix} when,barmagnet,receds,from \ the,conducting,loop \ end{matrix} right}Rightarrow begin{matrix} now,galvanometer,deflection,is \ ioperatorname{s},,opposite,to,the,previous,one \ end{matrix}$

As we know, deflection of galvanometer indicates an electric current induced in the given loop due to changing flux linked with the loop the loop behaves as there is an emf connected across it.

Faraday experimentally observed that, an emf induced in the loop, and the magnitude of the proportional to the negative rate of change of magnetic flux through the loop.

$left. begin{matrix} e=-frac{dphi }{dt} \ e=frac{d}{dt}(BAcos theta ) \ end{matrix} right}……..(1)$

For a coil

For a coil, consists of N no of loops then induced emf in the coil is N times of emf.

$e=-frac{Ndphi }{dt}…………(2)$

How magnetic flux linked with a loop is changing?

Since flux ϕ = BAcosƟ

Magnetic flux is changing due to

(i) change in magnitude of $overrightarrow{B}$

(ii) Change in Area $(overrightarrow{A)}$

(iii) orientation of loop with respect to $overrightarrow{B}$ (angle between $overrightarrow{B},and,overrightarrow{A}$ of loop)