Magnetic Flux

Sketch the change in flux, emf and force when a conducting rod $PQ$ of resistance $R$ and length $l$ moves freely to and fro between $A$ and $C$ with speed $v$ on a rectangular conductor placed in uniform magnetic field as shown in the figure.

When a bar magnet is pushed towards (or away) from the coil connected to a galvanometer, the pointer in the galvanometer deflects. Identify the phenomenon causing this deflection and write the factors on which the amount and direction of the deflection depends. State the laws describing this phenomenon.

Describe a simple experiment (or activity) to show that the polarity of emf induced in a coil is always such that it tends to produce a current which opposes the change of magnetic flux that produces it.

When is the magnetic flux taken as positive

Define magnetic flux. Compute its dimensions.

A magnet is moving towards a coil with a uniform speed $v$ as shown in the figure. State the direction of the induced current in the resistor $R$.

State the rule used to determine the direction of current induced in a conductor moving in a perpendicular magnetic field.

Write the dimensional formula of magnetic flux.

Name the SI unit of magnetic induction (or magnetic flux density).

Name the SI unit of magnetic flux.

A rectangular coil of $N$ turns and area of cross-section $A$, is held in a time-varying magnetic field given by $B=B_0\sin \omega t$, with the plane of the coil normal to the magnetic field. Deduce an expression for the emf induced in the coil.

A closed coil consists of $500$ turns on a rectangular frame of area $4.0 {\mathrm{cm}}^2$ and has a resistance of $50 \mathrm{\Omega }$. It is kept with its plane perpendicular to a uniform magnetic field of $0.2 \mathrm{Wb} {\mathrm{m}}^{-2}$. Calculate the amount of charge flowing through the coil when it is turned over (rotated through $180°$). Will this answer depend on the speed with which the coil is rotated?

A square coil of $600$ turns, each side $20 \mathrm{cm}$, is placed with its plane inclined at $30°$ to a uniform magnetic field of $4.5\times {10}^{-4}\mathrm{Wb} {\mathrm{m}}^{-2}$. Find the flux through the coil.

Find the magnetic flux linked with a rectangular coil of size $6 \mathrm{cm}\times 8 \mathrm{cm}$ placed at right angle to a magnetic field of $0.5 {\mathrm{Wbm}}^{-2}$.