Question

61. The potential difference between points A and B is




(a) 10 V
(c) 14 V
(b) 12 V
(d)0V​

Answer 1

Answer

Potential difference between points A and B is 0 V

$\orange{\bigstar}$  Given  $\green{\bigstar}$

A circuit is given having batteries of 6V , 9V and resistances 3 , 2Ω and current , I = 3 A

$\orange{\bigstar}$  To Find  $\green{\bigstar}$  

potential difference between points A and B

$\orange{\bigstar}$  Key Points  $\green{\bigstar}$  

You must know the sign rules before going to solve this problem

1 . If we are moving from positive to negative terminal , V is taken as negative and vice-versa

2 . If current is moving towards the resistance then voltage through resistance is take as negative and vice-versa

$\orange{\bigstar}$  Solution  $\green{\bigstar}$  

We need to find potential difference between points A and B

$\to \rm V_A-6+V_{2\Omega}-9+V_{3\Omega}=V_B\\\\\to \rm V_A-V_B=6+9-V_{2\Omega}-V_{3\Omega}\\\\\to \rm V_{AB}=15-(3)(2)-3(3)\\\\\to \rm V_{AB}=15-6-9\\\\\to \rm V_{AB}=15-15\\\\\to \rm \orange{\bigstar}\ \; V_{AB}=0\ V\ \; \green{\bigstar}$

So , Option (d) is correct

Answer 2

$\orange{\bigstar}$  Answer  $\green{\bigstar}$

Apply Loop Law ,

$\rm V_A+(-6)+(2)(3)+(-9)+(3)(3)=V_B\\\\:\to \rm V_A-V_B=6+9-6-9\\\\:\to \rm V_{AB}=0\ V\ \; \pink{\bigstar}$

The potential difference between the points A and B is 0 V

So , $\red{\bigstar}$  Option (d)  $\blue{\bigstar}$ is correct