Question

# Potentiometer wire length is 10 m, having a total resistance of 75 Ω and a battery of emf 200 V (of negligible internal resistance) connected to it as shown in figure. Find the value of x if P is a null point.

A
1 m
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
2 m
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C
3 m
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
4 m
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

## The correct option is B 2 mCurrent in the main circuit is, 200−25i−75i=0 i=2 A The potential gradient across the potentiometer wire will be ϕ=VABLAB=2×75LAB=15010=15 Vm−1 For null point, potential drop across wire of (10−x) m will be equal to emf (=120 V) of secondary battery. ∴ϕ(10−x)=120 V 15(10−x)=120 ∴x=2 m <!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Hence, (B) is the correct answer.

Suggest Corrections
0
Related Videos
Wheatstone Bridge
PHYSICS
Watch in App
Explore more