A variable, opposite external potential (E_ ext ) is applied to t…

MCQ

A variable, opposite external potential $(E_{ext})$ is applied to the cell $Zn\,|\,Z{n^{2 + }}\,(1\,M)\,\,||\,\,C{u^{2 + }}\,(1\,M)\,|\,Cu,$ of potential $1.1\,V.$ When $E_{ext} < 1.1\,V$ and $E_{ext} > 1.1\,V,$ respectively electrons flow from

A
anode to cathode in both cases
B
cathode to anode and anode to cathode
✓
anode to cathode and cathode to anode
D
cathode to anode in both cases

✓

Answer

Correct option: C.

anode to cathode and cathode to anode

c
$EMF$ of galvanic cell $= 1 .1\,volt$
If $E_{ext} < EMF$ then electron flows steadily from anode to cathode while If $E_{ext} > EMF$ there electron flows from cathode to anode as polarity is changed.

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