Question

A. Write two or three sentences to describe the conductivity of an insulator. Explain its conductivity in terms of the electrons in it.

b. What is resistance? How does the resistance of a long wire compare with the resistance of a short wire? How does the resistance of a thick wire that has a large cross sectional area compare with the resistance of a thin wire?

c. What is the power of a lightbulb that has a current of 1.46 A at 120. V?

Answer 1

a) Conductivity originates from the word "conduct" and is being used when talking about how good (high conductivity) or how bad (low conductivity) materials allow charge carriers (electrons in metals) pass through the material. Insulator must isolate things, i.e. it must not have free electrons or electrons with weak ties that can make current.

b) Resistance lessens currents. Resistance is like a tube: water passes through short and wide tube easily and the current hardly passes through a long and thin tube.

c) P=IV=1.46*120=175.2 W.

Answer 2

PART A)

Conductivity of insulator is very small as there is no free electrons to conduct the current trough that medium

So here number of conduction electrons are very less in insulators

PART B)

Resistance is the property of a conducting medium which will oppose the flow of current trough it

Resistance of wire directly depends on its length so resistance of long wire will be more than the resistance of short wire

Resistance inversely depends on the area so if a wire has more crossectional area then its resistance must be small

PART C)

power of light bulb is defined as rate of electrical energy

it is given by formula

P = i V

here we know that

i = 1.46 A

V = 120 volts

so power is given as

`P = 1.46 * 120`

`P = 175.2 Watt`