A student is given 4 identical batteries, each of emf 1.5 V and internal resistance 0.1 Ω. The student is asked to connect them in series in the assisting manner. By mistake he connects one battery the reverse way. The resultant emf and resultant internal resistance of the combination are .

Question

Accepted Answer

(1) 3 V, 0.4 Ω. Given: 4 batteries, each ε=1.5 V and r=0.1 Ω, in series with one reversed. Idea: in series the emfs add with sign (a reversed battery counts as negative), while internal resistances always add. Emf: three assisting and one opposing, 3×1.5-1.5=3 V. Equivalently 6-2×1.5=3 V: reversing one battery loses its 1.5 V and subtracts another 1.5 V. Internal resistance: 4×0.1=0.4 Ω, whatever the orientation. So the combination has 3 V and 0.4 Ω.

A student is given 4 identical batteries, each of emf 1.5 V and internal resistance 0.1 Ω. The student is asked to connect them in series in the assisting manner. By mistake he connects one battery the reverse way. The resultant emf and resultant internal resistance of the combination are ______.

Step-by-step solution

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