Question

The internal resistance of a primary cell is 4????. It generates
a current of 0.2 A in an external reistance of 21 ????. The rate
of chemical energy consumed in providing the current is
(a) 0.42 J s⁻¹ (b) 0.84 J s⁻¹
(c) 1 J s⁻¹ (d) 5 J s⁻¹

Answer 1

Answer:

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Explanation:

The rate of consumption of chemical energy = Rate of generation of electrical energy.

The energy generated is calculated from the formula P = VI. Substituting V=IR (Ohm's law) in the above equation we get,

Power=VI=I

2

R.

In this case, there are external and internal resistances. So, the equation is rewritten as I

2

(R+r).

Therefore, Chemical energy = 0.2

2

(4+2)=0.24J/s.

Hence, The rate at which chemical energy is consumed in providing the current is 0.24 J/s.