Neet Solved Paper 2013 Question 27
Question: The resistances of the four arms P, Q, R and S in a Wheat stone’s bridge are $ 10,\Omega ,30,\Omega ,30,\Omega $ and $ 90,\Omega , $ respectively. The emf and internal resistance of the cell are 7 V and $ 5,\Omega $ respectively. If the galvanometer resistance is $ 50,\Omega , $ the current drawn from the cell will be
Options:
A) 1.0 A
B) 0.2 A
C) 0.1 A
D) 2.0 A
Show Answer
Answer:
Correct Answer: B
Solution:
- Effective resistance, $ {R _{eff}}=\frac{40\times 120}{120+40}=\frac{4800}{160}=30,\Omega $
$ \therefore $ Current $ l=\frac{7}{(30+5)}=\frac{7}{35}=0.2A $ $ [ \because l=\frac{E}{R+r} ] $
