Question

State Joule's law of heating. List two special characteristics of a heating element wire.
An electronic iron consumed energy at the rate of 880 W when heating is at the maximum rate and 440 W
when the heating is at the minimum rate. The applied voltage is 220 V. Calculate the current and
resistance in cach case
Question 2
Copper and aluminum wires are usually employed for electricity transmission. Why?
Question 3
Derive the expression for the heat developed in a resistor hy the passage of electric current through it. 220
J of heat is produced each second in a 8 ohm resistor. Find the potential difference across the resistor.
Question 4
Write two important differences between electrical resistance and resistivity.
Onestion 5​

Answer 1

Answer:

Explanation:

The joule’s first law shows the relationship between heat produced by a flowing electric current through a conductor.

Q = I2 R T

Where,

Q indicates the amount of heat

I show electric current

R is the amount of electric resistance in the conductor

T denotes time

The amount of generated heat is proportional to wire’s electrical resistance when the current in the circuit and the flow of current is not changed.

The amount of generated heat in a conductor carrying current is proportional to the square of the current flow through the circuit when the electrical resistance and current supply is constant.

The amount of heat produced because of the current flow is proportional to the time of flow when the resistance and current flow is kept constant.