question_answer

In the given circuit the internal resistance of the 18 V cell is negligible. If \[{{R}_{1}}\,\,=\,\,400\,\Omega \],  \[{{R}_{3}}=100\text{ }\Omega \] and \[{{R}_{4}}=500\Omega \]and the reading of an ideal voltmeter across \[{{R}_{4}}\] is 5 V, then the value of \[{{R}_{2}}\] will be: [JEE Main 09-Jan-2019 Evening]

A) \[550\,\,\Omega \]

B) \[450\,\,\Omega \]

C) \[230\,\,\Omega \]

D) \[300\,\,\Omega \]

Correct Answer: D

Solution :

[d]

or

So, V across  will be  volt

Total current

I across  Amp.

Now

So,