Question 460: Current Electricity

Question

The ratio of the equivalent resistance of the network (shown in figure) between the points a and b when switch is open and switch is closed is x : 8. The value of x is ___________.

Accepted Answer

$${R_{eq\,open}} = {{3R} \over 2}$$
$${R_{eq\,closed}} = 2 	imes {{R 	imes 2R} \over {3R}} = {{4R} \over 3}$$
$${{{R_{eq\,open}}} \over {{R_{eq\,closed}}}} = {{3R} \over 2} 	imes {3 \over {4R}} = {9 \over 8}$$
$$	herefore$$ $$x = 9$$

Current Electricity

The ratio of the equivalent resistance of the network (shown in figure) between the points a and b when switch is open and switch is closed is x : 8. The value of x is ___________.

Choose the correct answer: