Which of the following statements is incorrect regarding viruses?

What is the meaning of the word 'ease' in French?

Each pair forms an ideal solution except:

Two unit negative charges are placed on a straight line. $A$ positive charge $q$ is placed exactly at the midpoint between these unit charges. If the system of these three charges is in equilibrium,the value of $q$ (in $C$) is

How many $g$ of a dibasic acid $(Mol. wt. = 200)$ should be present in $100 \ ml$ of its aqueous solution to give a decinormal strength?

The angle of elevation of a stationary cloud from a point $2500 \ m$ above a lake is $15^{\circ}$ and from the same point the angle of depression of its reflection in the lake is $45^{\circ}$. The height (in metres) of the cloud above the lake,given that $\cot 15^{\circ}=2+\sqrt{3}$,is