Question

The equivalent resistance between the points P and Q in
the network shown in the figure is given by
(A)2.5 ohms
(B)7. 5 ohms
(C)10. ohms
(D)12.5 ohms​

Answer 1

Question :

The equivalent resistance between the points P and Q in the network shown in the figure is given by :

Theory :

• Resistors in series and parallel

1) Resistors in series :

For n resistors connected in series

the equivalent Resistance $R_{eq}$ is given by :

$R_{eq}=R_{1}+R_{2}+R_{3}+...+R_{4}$

2) Resistors in parallel:

For n resistors connected in parallel

the equivalent Resistance $R_{eq}$ is given by :

$\dfrac{1}{R_{eq}} = \dfrac{1}{R_{1} } + \dfrac{1}{R_{2} } + \dfrac{1}{R_{3} } + ...... \dfrac{1}{R_{n} }$

Solution :

The given circuit is complex ,try to make it easier as shown in attachment.

Now we observed that the arrangement of four Resistors in wheat stone briged .

⇒The potential difference accross 20 ohm resistor is zero .

${\purple{\boxed{\large{\bold{R_{eq}=7.5\:ohm}}}}}$

For step by step explanation refer to the attachment

___________________________

correct option b)

Answer 2

ANSWER IS IN ATTACHMENT...

(Question is something different...but same base Question)

HOPE IT HELPS YOU