Riemann's green is a green pigment ZnO.CoO, which is obtained by heating a mixture of zinc oxide and cobalt nitrate or by the reaction of cobalt nitrate with either 3Zn(OH)2ZnCO3 or zinc sulphate.

SinceECu2+/CuECu2+/Cuhas a greater positive value thanEH+/HEH+/H, the reaction that is feasible at the cathode is

Cu2+(aq)+2eCu(s)

Log_2aa=x    then, a=(2a)^x  ......(1)

Log_3a2a=y    then,2a=(3a)^y ......(2)

Log_4a 3a=z  then, 3a=(4a)^z ......(3)

So, 

a=(2a)^x  [from (1)]

Or, a=(3a)^xy    [from(2)]

Or, a=(4a)^xyz     [from(3)]

Multiplying both sides by 4a,

4a.a=4a.(4a)^xyz  

Or,(2a)² =(4a)^{xyz + 1} 

Or,(3a)^2y =(4a)^xyz+1 

Or,(4a)^2yz =(4a)^xyz+1 

Or, 2yz = xyz+1 .proved.

1.ans:  No the tension in the string of a simple pendulum is not constant throughout the motion                                     

v is velocity of the bob and theta is the angle made by the string with vertical axis.

as v and θ both are variable T is also variable.

T is maximum at mean position as at mean position v is max and the angle is minimum.

2.ans: If the amplitude of the simple...