How does the balancing length of a potentiometer change on increasing the resistance offered by the rheostat that is connected in series with the primary cell. *

Asked by imranhussain3273 | 23rd Sep, 2021, 01:54: PM

Expert Answer:

Balance length l1 is determined by the following equation using the principle of Wheatstone bridge

begin mathsize 14px style R over S equals space fraction numerator R subscript c m end subscript l subscript 1 over denominator R subscript c m end subscript left parenthesis 100 minus l subscript 1 right parenthesis end fraction space equals fraction numerator l subscript 1 over denominator left parenthesis 100 minus l subscript 1 right parenthesis end fraction space end style
 
Where R is unknown resistance , S is known resistance and Rcm is resistance of ptentiometer per cm .
 
We see from above expression, while finding the balancing length, resistance per unit length of potentiometer
is cancelled between numerator and denominator.
 
Hence resistance of potentiometer wire will not affect the balancing length.

Answered by Thiyagarajan K | 24th Sep, 2021, 05:39: PM