Question

With the help of a circuit diagram, obtain the relation for the equivalent resistance of two resistances
connected in parallel.
) in the circuit diagram shown below, find :
(q) Total resistance.
(b) Current shown by the ammeter A​

Answer 1

Answer:

Explanation:

Suppose total current flowing the circuit is I. Then the current passing through resistance R  

1

​  

 will be I  

1

​  

 and the current passing through resistance R  

2

​  

 will be I  

2

​  

 

Total current =I=I  

1

​  

+I  

2

​  

 

Let resultant resistance of this parallel combination is R. By applying ohm's law to the whole circuit, we get that I=V/R

Since the potential difference across both the resistance is the same. So applying the ohm's law to each resistance we get that  

I  

1

​  

=V/R  

1

​  

 

I  

2

​  

=V/R  

2

​  

 

Putting these eq in the above one, we get that

V/R=V/R  

1

​  

+V/R  

2

​  

 

1/R=1/R  

1

​  

+1/R  

2

​  

 

If two resistance are connected in parallel than the resultant resistance will be

1/R=1/R  

1

​  

+1/R  

2

​  

 

(b)  

(i) Total resistance = R

1/R=1/R  

1

​  

+1/R  

2

​  

 

R  

2

​  

=3+2=5ohms

R  

1

​  

=5ohms

1/R=2/5

R=2.5ohms

(ii) Current through the circuit

I=V/R=4/(2.5)

=1.6amps

solution