Question

A Wheatstone bridge has the resistances $10\, \Omega,\, 10\, \Omega, 10\, \Omega$ and $30\, \Omega$ in its four arms. What resistance joined in parallel to the $30\, \Omega$ resistance will bring it to the balanced condition?

• A. $2\, \Omega$
• B. $5\, \Omega$
• C. $10\, \Omega$
• D. $15\, \Omega$

Answer 1

Answer: (D)

$15\, \Omega$

Answer 2

In balanced Wheatstone bridge,
$\frac{1}{10}=\frac{1}{x} +\frac{1}{30}$
$x=15\, \Omega$