Current Electricity Charging Discharging Of Capacitors Question 746

Question: A battery of emf $ E _{0}=6V $ is connected across a 2m long uniform wire having resistance $ 4\Omega /m. $ The cell of small emf $ {\varepsilon _{1}}=2V $ and $ {\varepsilon _{2}}=3V $ having internal resistance $ 2\Omega ,\And ,1\Omega $ respectively are connected as show in the figure. The null point will be obtained at

Options:

A) 0.10m

B) 0.25m

C) 0.50m

D) 0.75m

Show Answer

Answer:

Correct Answer: D

Solution:

[d] Effective emf of two cells in parallel $ \varepsilon =\frac{{\varepsilon _{2}}r _{1}-{\varepsilon _{1}}r _{2}}{r _{1}+r _{2}}=\frac{3\times 2-2\times 1}{2+1}=\frac{4}{3}V $ X terminal of the connection is positive. For neutral point, positive terminal of $ {\varepsilon _{0}} $ must be connected to X.