Question

Seven resistances, each of value 20 $\Omega$, are connected to a 2 V battery as shown in the figure. The ammeter reading will be

• A. 1/10 A
• B. 3/10 A
• C. 4/10 A
• D. 7/10 A

Answer 1

The correct option is C 4/10 A

The equivalent resistance for first three resistors is $=R/3$ and for last four resistors $=R/4$ because they are in parallel.
Here the ammeter reading is $i_2$
now apply Kirchhoff's law for outermost loop, $2=\left(R/4\right)i_2\Rightarrow i_2=\frac{8}{R}=8/20=4/10A$