question_answer

A filament bulb (500W, 100V) is to be used in a 230V main supply. When a resistance R is connected in series, it works perfectly and the bulb consumes 500W. The value of R is:

A) 13Q    

B)               230Q    

C) 46Q                             

D) 26Q

Correct Answer: D

Solution :

[d] \[P=VI\] \[500=1001\] \[I=5A\] \[{{V}_{R}}\left( across\,\,R \right)\text{ }=230130\] \[{{V}_{R}}=130V\] \[130=5R\] \[R=26\Omega \]