The correct answer is (C. zirconium - 93.
Answer : The retention time is, 20 min
Explanation :
Retention time : It is defined as the amount of time a compound spends on the column after it has been injected.
Formula of retention time is:

Given:
Distance from injection point to center of peaks = 10 cm
Chart recorded speed = 0.5 cm/min
Now put all the given values in the above formula, we get:

Retention time = 20 min
Thus, the retention time is, 20 min
Lifting the backpack off the floor. Force is being applied in only one direction then (up) which is what constitutes as work. Carrying the box of crayons applies force in two directions (up and forward), which cancel each other out. Work has a vector, which is a quantity containing both direction and magnitude (one, finite direction, not two).
Answer:
To allow all the elements or compounds to separate complete.
Explanation:
In chromatography, the compounds need some space and time to separate, one from each other, if you just use the half of the paper strip maybe you will not notice the different spots of compounds. Remember all the substances have different affinity for the solvents, that means, some react very quickly but others need more time as the colors that conform the black color in an ink.