Question

State joules law of heating list two special characteristics of heating element wire

Answer 1

Explanation:

Joule's law of heating :

If current flowing ( I ) in conductor having resistance ( R ) for time ( T ) then

they all will be directly proportional to square to current , resistance and time.

H = I² R T.

Two special characteristics of heating element wire are :

1. They have high melting points.

2. They have high resistivity.

For example :

Nichrome & alloy of nickel and chromium.

Taking one example of joules law of heating

Calculate the Resistance of conductor which has flowing 2 A current for time 1 minute and heated 480 J.

Here we have to find resistance.

Given :

I = 2 A

T = 1 min = 60 sec

H = 480 J

We put formula

H = I² R T.

Put the value here

480 = 4 × 60 × R

240 R = 480

R = 2 Ω

Thus the Resistance of conductor is 2 Ω.