Question

[Physics]
State joules law of heating and express it mathematically.

••••Plagiarism strictly prohibited in my questions.​

Answer 1

Answer:

Joules law states that

The heat produce in the conductor is directly proportional to the square of Current .

• H ∝ I² ------------(i)

The heat produce in the conductor is directly proportional to the resistance .

• H ∝ R ------------(ii)

The heat produce in the conductor is directly proportional to the time taken to flow the current .

• H ∝ T --------------(iii)

From equation (i) , (ii) & (iii) we get

→ H ∝ I²RT

→ H = KI²RT

where, K is constant propostionality . ( It means K = 1)

→ H = 1 × I²RT

→ H = I²RT

• Hence, the mathematical expression of Joules law is H = I²RT.

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Answer 2

Lets do:-

We know that

• The energy required For a cell providing Q amount of charge between t time is W=VQ

We know

$\boxed{\sf Power(P)=\dfrac{W}{t}}$

$\\ \sf\longmapsto P=\dfrac{VQ}{t}$

• Putting I=Q/t

$\\ \sf\longmapsto P=VI$

$\\ \sf\longmapsto Pt=VIt$

• It converts to heat in resistor.

$\\ \sf\longmapsto H=VIt$

• Putting ohms law V=IR

$\\ \sf\longmapsto H=IR\times It$

$\\ \sf\longmapsto H=I^2Rt$

It is known as Joules law of heat.

Key words:-

• Work done=W
• Time=t
• Charge=Q
• Potential Difference=V
• Current=I
• Heat=H
• Resistance=R
• Power=P