Question

1.a.Define the term resistivity.
b. What is earth wire
c. What is electromagnetic induction hey

Answer 1

a.
Resistivity of a conductor is the ability of the material of the conductor to oppose the flow of current .
SI unit: ohm-meter. Following is the equation relating resistivity (ρ) and resistance (R) of a conductor of length (L) and area (A).

R = ρl/A
ρ = RA/l

Resistivity is the resistance of the material with unit area of cross section and unit length.

b.
The earth wire in a 3-pin plug connects an electrical appliance to the earth. When a loose live wire touches the metal part of an appliance, the electric current will flow to the ground through the earth wire. This prevents a person who touches the metal part of the appliance from getting an electric shock.

c.
Electromagnetic or magnetic induction is the production of an electromotive force across an electrical conductor in a changing magnetic field.