How to solve these kind of potentiometer questions

Asked by nipunverma59 | 12th Apr, 2019, 04:07: PM

Expert Answer:

l e t space u s space a s s u m e space t h e space r e s i s tan c e space t o space b e space s o m e space R space
a n d space t h e space c e l l space h a s space r e s i s tan c e space o f space space 2 space o h m
n e t space e q u i v a l e n t space r e s i s tan c e space i f space t h e space c i r c u i t space equals space R space plus space 6 plus 2 equals R plus 8
n e t space v o l y a g e b o f space t h e space c i r c u i t space equals space 4 V
u sin g space o h m s space l a w space n e t space c u r e e n t space i f space t h e space c i r c u i t space I space equals V over R space equals fraction numerator 4 over denominator R plus 8 end fraction
v o l t a g e space a c r o s s space w i r e space equals space I cross times r e s i s tan c e space equals space fraction numerator 4 cross times 6 over denominator R plus 8 end fraction space equals space fraction numerator 24 over denominator R plus 8 end fraction
p o t e n t i a l space g r a d i e n t space equals space fraction numerator v o l t a g e over denominator l e n g t h end fraction space equals space fraction numerator 24 over denominator 200 cross times left parenthesis R plus 8 right parenthesis end fraction
a n d space i t s space g i v e n space t h i s space v a l u e space i s space e q u a l space t o space 0.001 V divided by c m
s o
fraction numerator 25 over denominator 200 cross times left parenthesis R plus 6 right parenthesis end fraction space equals 0.001
w e space g e t space v a l u e space o f space R space equals space 120 minus 8 space equals space 112 space o h m
s o b y h e space c o r r e c t space o p t i o n space i s space D space w h i c h space h a s space n e a r e s t space v a l u e space t o space 114 space o h m

Answered by Ankit K | 13th Apr, 2019, 07:59: AM