Current Electricity Ques 115 — JEE PYQ Chapterwise

Answer:

Correct Answer: 115.(c)

Solution:

Formula:

Electrical Power:

115. Colour code of carbon resistance is shown in the figure below

So, resistance value of resistor using colour code is

$ R=502 \times 10=50.2 \times 10^{2} \Omega $

Here, we must know that for given carbon resistor first three colours give value of resistance and fourth colour gives multiplier value.

Now using power, $P=i^{2} R$

$ \text { we get, } \quad \begin{aligned} i & =\sqrt{\frac{P}{R}}=\sqrt{\frac{2}{50.2 \times 10^{2}}} \\ & \simeq 20 \times 10^{-3} A=20 mA . \end{aligned} $