A group of N cells where e.m.f. varies directly with the internal resistance as per the equation `E_(N)=1.5r_(N)` are connected as shown in the figure. The current I in the circuit is:

Options

A. 0.51 amp
B. 5.1 amp
C. 0.15 amp
D. 1.5 amp

Answer

D

Explanation

`i=(sum_(0)^(n)E_(n))/(sum_(0)^(n)r_(n)) = (E_(1) +E_(2) +E_(3) +…..+ E_(n))/(r_(1) + r_() + r_(3) + …. _+ r_(n))`
`= (1.5 r_(1) + 1.5 r_(2) + 1.5 r_(3) + …. + 1.5 r_(n))/(r_(1) + r_(2) + r_(3) ……. + r_(n))`
`i=1.5 A`