After some time, we shall note that there is no change
in the concentration of Cu2+ and Zn2+ ions and at the same time,
voltmeter gives zero reading This indicates that equilibrium has been
attained In this situation the Nernst equation may be written as:
E(cell) = 0 = 
(
)
o
Ecell
 – 
2 303
2
log [Zn
]
[Cu
]
2
2
RT
F
+
+
or 
(
)
o
Ecell
 = 
2
2
2