Question

find the minimum number of cells required to produce an electric current of 1.5A through a resistance of 30 ohm.Given that emf of cell is 1.5 V and internal resistance is 1 ohm.

Answer 1

the minimum number of cells is 1

Answer 2

Answer:

The correct answer is 120.

Explanation:

Given:

Ampere= 1.5

Resistance=30 ohm

EMF of a cell is 1.5 volts

Internal resistance is 1 Ohm

Let us take current as I  with maximum.

$I_{max} = 2E/ 2r = nE/ 2R$ ____________(1)

Here n is called the number  of cells in each rows.

And m is called the number of rows that is present.

Hence, $I_{max} = 1.5 , n = 1.5 , E =mR=1$

By putting the value in the equation (1) we get,

$1.5 = 1.5*m/ 2*1$

$m = 2$

Therefore, the total number of cells will be

$n * m = 2*60=120$

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