Q.

A potentiometer wire of length 100 cm  has a resistance 5 ohm . It is connected in series with a resistance and a cell of emf 2 V  and of negligible internal resistance. A source of emf 5 mV  balanced by 10 cm  length of potentiometer wire. The value of external resistance is_____

see full answer

Talk to JEE/NEET 2025 Toppers - Learn What Actually Works!

Real Strategies. Real People. Real Success Stories - Just 1 call away
An Intiative by Sri Chaitanya

a

540 Ω

b

195 Ω

c

190 Ω

d

990 Ω

answer is B.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

Potentiometer wire of length L=100 cm Resistance R=5 Ω Cell of emf E=2 V Source of emf E1=5 mV Balancing length l=10 cm E1=(ER+RS) RLl 5×10−3=(25+RS) 5100×10 5×10−3=2×5×10(5+RS)100 ∴RS= 195 Ω
Watch 3-min video & get full concept clarity
Related Blogs
Get ₹ 1 crore* worth scholarship for JEE / NEET / Foundation
Result Producing online coaching for JEE/NEET of south India
Largest All India Test Series for JEE/NEET
Best Online Course for IIT JEE
Best Online Course for NEET
Best Online Course for CBSE
score_test_img

Get Expert Academic Guidance – Connect with a Counselor Today!

Related Blogs
Get ₹ 1 crore* worth scholarship for JEE / NEET / Foundation
Result Producing online coaching for JEE/NEET of south India
Largest All India Test Series for JEE/NEET
Best Online Course for IIT JEE
Best Online Course for NEET
Best Online Course for CBSE
whats app icon