Q. Which of these is a unit of measurement of water potential/osmotic pressure?
(a) Watts
(b) Joule
(c) Pascal
(d) Litre
Solution :
Correct option : C
Water potential is denoted by the Greek letter ψ (psi). It is the measure of the relative tendency of water to move from one area to another and are measured in the terms of bars, which is expressed in units of pressure (pressure is a form of energy) called megapascals (MPa). It is the difference between the free energy of water molecules in pure water and solution. Water potential can be measured using the formula, ψ = ψs + ψp where ψs = Solute Potential or Osmotic Potential and ψp = Pressure Potential or Turgor Potential. Here, the water movement across the concentration gradient will be higher water potential to lower water potential. So, the correct answer is option C.
