question_answer

A 2 W carbon resistor is color coded with green, black, red and brown respectively. The maximum current which can be passed through this resistor is- [JEE Main Online Paper (Held On 10-Jan-2019 Morning]

A) 0.4 mA                         

B) 20 mA

C) 63 mA              

D)   100 mA

Correct Answer: B

Solution :

From colour code table \[R=50\times {{10}^{2}}=500\,\Omega \] \[Power=2\text{ }watt\] \[2={{i}^{2}}R\] \[2={{i}^{2}}\times 5000\] \[\frac{0.4}{1000}\,=\,{{i}^{2}}\] \[i\,\,=\,\,\frac{2}{100}\,Amp\,\,=\,\,20\,mA\]