Question

12)a) Derive the expression for Joule's law of beating, b) Derive a formula for four equivalent resistances connected in series,​

Answer 1

Answer:

Explanation:

a)

P  = VI  

H = P × t = Vlt

But             V = IR (ohm's law)  

∴                H = I2Rt

b)

V = V1 + V2 + V3

we know that V = IR

∴ V1 = IR1

    V2 = IR2  

    V3 = IR3  

But              V = V1+ V2 + V3

                      => IR = IR1 + IR2 + IR3

                       => IR = I(R1 + R2 + R3)

                      =>$\frac{ IR}{I}$ = R1 + R2 + R3

                       => R = R1 + R2 + R3