ch6: EMI

What does the negative sign in Faraday's law represent?

lenz's law induced EMF opposes the change producing it

EMF = ? (faraday’s 2 nd law wala)

Which formula should I use if the conductor is moving?

Motional emf: $\epsilon=Bvl$

Magnetic Flux (phi)?

$$\phi=b.ds$$

A rod moving in a magnetic field has resistance R. What is the induced current?

$$\frac{Bvl}{R}$$

What force opposes the motion of a conducting rod moving in a magnetic field?

$$\frac{B^2vl^2}{R}$$

a rod of length l moves with speed v perpendicular to magnetic field B, what is the induced EMF

$\epsilon=Bvl$ (works only when B,v,l are all perpendicular)

What is the mechanical power required to move the rod at constant velocity? (motional emf)

$$P=Fv$$

$$\frac{B^2v^2l^2}{R}$$

What is the motional emf across a rod rotating about one end?

What is the induced emf produced due to self-induction?

\epsilon=-\frac{LdI}{\differentialD t}

What is the self-inductance of a long solenoid?

$$\mu.{}\frac{N^2A}{l}$$

If the number of turns doubles in a long solenoid, what happens to self-inductance?

Four times because L is directly proportional to N²

Define coefficient of self-inductance. and it’s mathematical expression. L=?

Flux linkage per unit current.

$\frac{Nd\phi}{I}$ (si unit: henry)

Define mutual inductance. and it’s mathematical expression

Flux linkage in one coil produced by current in another coil per unit current.

$$M_{21}=\frac{N_2\phi_2}{I_1}$$

EMF due to mutual induction in wire 2 with respect to wire 1

What is the mutual inductance of two long coaxial solenoids?

Energy stored in an inductor? (for a coil)(or maybe not)

$$U=W$$

What is the instantaneous emf produced by an AC generator?

What is the maximum (peak) emf of an AC generator?

What is the instantaneous current in an AC generator connected to a resistance?

What is the peak current in an AC circuit with resistance R?

in magnetic flux, theta is the angle b/w?

between the magnetic field (B) and the area vector (normal to the surface).