Question

(C) Ⓡ Three identical resistors R1, R2 and
Rz are connected to a battery as shown
in the figure. What will be the ratio of
voltages across R1 and R2? ​

Answer 1

Correct option is

A

V  

1

​

=V  

2

​

 and R  

1

​

=R  

2

​

=R  

3

​

 

B

V  

1

​

=V  

2

​

 and R  

1

​

=2R  

2

​

=R  

3

​

 

D

2V  

1

​

=V  

2

​

 and 2R  

1

​

=R  

2

​

=R  

3

​

 

Writing Kirchoff's laws for the top and bottom loops ,  

V  

1

​

−i  

1

​

R  

1

​

−(i  

1

​

−i  

2

​

)R  

2

​

=0

V  

2

​

−i  

2

​

R  

3

​

+(i  

1

​

−i  

2

​

)R  

2

​

=0

If Current through R  

2

​

 is zero , i  

1

​

=i  

2

​

 

Substituting in the above equations, we get:  

V  

2

​

 

V  

1

​

 

​

=  

R  

3

​

 

R  

1

​

 

​

 

Substituting the values given in the options and verifying,  

options A , B and D satisfy this condition.