Question

A current in circuit is given by i = 4+3cos wt the effective value of current

Answer 1

ye Science he ya math

Answer 2

If an instantaneous current is written as $\bf{I=I_{dc}+I_{ac}}$. where Idc denotes direct current and Iac denotes alternating current.

in wave general form, $I=a+bsin\omega t$.....(1)

where a denotes direct current and $bsin\omega t$ denotes alternatively current.

Then, effective current is given by, $I_{eff}=\sqrt{a^2+\frac{b^2}{2}}$

Given, I = 4 + 3cosωt.....(2)

comparing equations (1) and (2),

we get, a = 4 and b = 3

Now, $I_{eff}=\sqrt{4^2+\frac{3^2}{2}}$

= √(16 + 4.5)

= √(20.5) A

Hence, answer is √(20.5) A