Question

Question 12:
(a) State and explain Joule’s law of heating.
(b) A resistance of 40 ohms and one of 60 ohms are arranged in series across 220 volt supply. Find the heat in joules produced by this combination of resistances in half a minute.

Lakhmir Singh Physics Class 10

Answer 1

hey mate here is your answer

Answer 2

Answer:

Part  ( a )

According to Joule ' s law it stats that the amount of heat generated inside a conductor is directly proportional to the  square of current and time for which current is paused

$H=I^{2}\times R\times T$

Part  ( b )

H = 14520 Joule

Explanation:

Part  ( a )

According to Joule ' s law it stats that the amount of heat generated inside a conductor is directly proportional to the  square of current and time for which current is paused

$H=I^{2}\times R\times T$

Part  ( b )

We have been given by the

Resistance R ₁= 60 Ω and  R ₂ = 40 Ω  are arranged in series

Voltage v  = 220 V

Time t = half minute

t = 30 s

Now

We know that

If Equivalent resistance in  series R = R₁ + R ₂

Equivalent resistance is R = 40 Ω + 60 Ω  = 100 Ω

Therefor we know that

H = $\dfrac{v ^2\times t}{R}$

H = $\dfrac{220\times 200\times 30}{100}$

H = 14520 Joule