Question

A) What is Electrical Resitivity (macroscopically)? Provide a microscopic interpretation with a sketch also:

B) What is an EMF? Explain:

C)What is Ohm's Law? Provide a graphical relationsip and interpretaions regarding current, voltage, and resistance:

Answer 1

A. resistivity of material is given by Rho = RA/L

resistiivity isn the ressiatcne offered by material of unit length and unit area of cross section

Rho is measured in ohm -m

i.e at L =1, and A = 1m^2 , Rho = R

since resistance is veaired accoring to the length , for a fixed dimensions of Land A , resistacne R = rho

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indiced emf in a coil is definmed as the the rate at which magntic flux across a coil changes

1.e induced emf is defiend as the rate of change of magnetic flux

in mathematical form,

induced emf e = NAdB/dt

where A = area

N = no. of tunrs

dB/dt = rate of change of amgnetic flux

we can also find induced cuurent as

induced current i = e/R

where R = resisatnce

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ohms law states that V   = iR

i.e the current acrosss the terminals of a conductor is directly porportial PD acroos its ends

matrials that obey ohms law are called ohmic conductors

and that doesnot obey are called non ohmic conductors