The $emf$ (in $V$) of a Daniell cell containing $0.1 \ M$ $ZnSO_4$ and $0.01 \ M$ $CuSO_4$ solutions at their respective electrodes is
$(E_{Cu^{2+} / Cu}^{\circ} = +0.34 \ V; E_{Zn^{2+} / Zn}^{\circ} = -0.76 \ V)$

The standard reduction potentials of $Zn^{2+}|Zn$,$Cu^{2+}|Cu$ and $Ag^{+}|Ag$ are respectively $-0.76 \ V$,$0.34 \ V$ and $0.8 \ V$. The following cells were constructed:
$(1)$ $Zn|Zn^{2+}||Cu^{2+}|Cu$
$(2)$ $Zn|Zn^{2+}||Ag^{+}|Ag$
$(3)$ $Cu|Cu^{2+}||Ag^{+}|Ag$
What is the correct order of $E_{cell}^{\circ}$ of these cells?

Two friends $A$ and $B$ are $30 \, km$ apart and they start simultaneously on motorcycles to meet each other. The speed of $A$ is $3$ times that of $B$. The distance between them decreases at the rate of $2 \, km$ per minute. Ten minutes after they start,$A$'s vehicle breaks down and $A$ stops and waits for $B$ to arrive. After how much time (in minutes) since $A$ started riding,does $B$ meet $A$?

If $\sqrt{x} + \frac{1}{\sqrt{x}} = 2\cos \theta$,then ${x^6} + {x^{-6}} = $

$(\sim (p \vee q)) \vee (\sim p \wedge q)$ is logically equivalent to

The anode mud in the electrolytic refining of silver contains