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 electroplaques 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 .............. $A$
A$1.5$
B$3$
C$15$
D$30$
AIIMS 2004, Diffcult
Download our app for free and get started
A$1.5$
a (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 $
$i = \frac{{5000 \times 0.15}}{{500 + \frac{{5000 \times 0.25}}{{100}}}}$$ = \frac{{750}}{{512.5}}$ $ \approx 1.5\,A$
Download our app
and get started for free
Experience the future of education. Simply download our apps or reach out to us for more information. Let's shape the future of learning together!No signup needed.*
In the circuit shown, current through $R_2$ is zero. If $R_4 = 2\,\Omega $ and $R_3 = 4\,\Omega $ , current through $R_3$ will be ................. $\mathrm{A}$
In a potentiometer (see figure) a balance is obtained at a length of $400\ mm$ when using a known battery of emf $1.6\ V$. After removing this battery, another battery of unknown emf is used and balance is obtained at a length of $650\ mm.$ The emf of unknown battery is ............. $volt$
The actual value of resistance $R$, shown in the figure is $30\,\Omega $. This is measured in an experiment as shown using the standard formula $R = \frac{V}{I}$ where $V$ and $I$ are the readings of the voltmeter and ammeter, respectively. If the measured value of $R$ is $5\%$ less, then the internal resistance of the voltmeter is ................. $\Omega$
Two resistors $400\, \Omega$ and $800\, \Omega$ are connected in series across a $6 V$ battery. The potential difference measured by a voltmeter of $10\, k \Omega$ across $400\, \Omega$ resistor is close to$....V$