Q. Eels are able to generate current with biological cells called electroplaques. The electroplaques in an eel are arranged in 100 rows, each row stretching horizontally along the body of the fish containing 5000 electroplaques. The arrangement is suggestively shown below. Each electroplaque has an emf of $0.15\ V$ and internal resistance of $0.25\ \Omega$ The water surrounding the eel completes a circuit between the head and its tail. If the water surrounding it has a resistance of $500\ \Omega,$ the current an eel can produce in water is about
A) $1.5\ A$
B) $3.0\ A$
C) $15\ A$
D) $30\ A$
Explanation
(a) Given problem is the case of mixed grouping of cells
So total current produced $i = \frac{nE}{R + \frac{nr}{m}}$
Here $m = 100,\ n = 5000,\ R = 500\Omega$
$E = 0.15\ V$ and $r = 0.25\Omega$
$\Rightarrow i = \frac{5000 \times 0.15}{500 + \frac{5000 \times 0.25}{100}} = \frac{750}{512.5} \approx 1.5\ A$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.