In dimensional analysis, a dimensionless quantity is a quantity to which no physical dimension is assigned, also known as a bare, pure, or scalar quantity or a quantity of
dimension one
, with a corresponding unit of measurement in the SI of the unit one (or 1), which is not explicitly shown.
Which is unitless quantity?
Hint: Unitless means
something which doesn’t have a unit
. Dimension depicts the quantity of a substance in a particular case. A substance can have a unit even if it doesn’t have a dimension.
Which is unit less quantity in chemistry?
Molarity
is measured as and the unit is Molar or moles per liter. Mole fraction is calculated as and it does not have units as it is a fraction. Mass Percent is calculated as and it is unitless as it is a ratio multiplied by 100. The correct answers are (iii) and (iv).
Which is unit less physical quantity?
Certain quantities are defined as the ratio of two quantities of the same kind, and are thus
dimensionless
. A dimensionless physical quantity may have an unit (e.g. Mechanical equivalent of heat) but a unitless physical quantity is always dimensionless (e.g. Coefficient of friction , refractive index).
Which of the following is dimension less quantity?
Optical density
is the ratio of the speed of light in two media. As optical density is the ratio of two similar physical quantities, therefore it is the dimensionless quantity.
What is a unit less quality?
A unit less quantity is the
one in which there are no fundamental quantities involved
. It doesn’t have any unit and hence it doesn’t have any dimensions. The dimension is Zero. Examples are, angle, elastic strain, Poisson’s ratio etc.
Can a dimensionless quantity exist?
Dimensionless quantities on the other hand are the
quantities which do not possess any dimensions
. … But when we look at the dimensionless quantity- angle, it has a unit assigned to it, the radians or degrees. So we cannot say that all dimensionless quantities are unit-less. Thus the correct answer is option C.
What is the unit of molarity?
The units of molarity are
M or mol/L
. A 1 M solution is said to be “one molar.”
Is stress a dimensionless quantity?
$dimensionless. Hint: We can define stress as the
reactive force per unit area
. Mathematically it is defined as the ratio of force and area of cross-section. Keeping the characteristics of stress in mind we will find the correct option.
What is the value of 1 mole?
One mole of a substance is equal to
6.022 × 1023 units
of that substance (such as atoms, molecules, or ions). The number 6.022 × 1023 is known as Avogadro’s number or Avogadro’s constant. The concept of the mole can be used to convert between mass and number of particles.. Created by Sal Khan.
Is refractive index is dimensionless quantity?
n is the refractive index of the medium. v is the velocity of light in that particular medium. c is the velocity of the light in vacuum. So, we can say that the refractive index is a
dimensionless quantity
.
What is the unit of strain?
Hence the unit of Strain is
mm/mm
. Therefore Strain has no unit. Hence it is a dimensionless term. The ratio of change in length to the original length is called the longitudinal strain.
Can a physical quantity have a unit but still dimensionless?
The answer is Yes,
There are such unit quantities, but dimensional quantities
. Note: The dimension quantity with one as a quantity that is not associated with any physical dimension. … In Maths and Physics, these dimensionless quantities are regularly used.
What unit is used for work?
One joule
is defined as the amount of work done when a force of one newton is exerted through a distance of one meter. In the English system of units, where force is measured in pounds, work is measured in a unit called the foot-pound (usually abbreviated ft-lb).
What is the dimensional formula of CR?
Explanation: Capacitance C = charge/potential difference Dimensions of c = [AT]/[ML2T-3A-1] = [M-1L-2T4A2] Resistance R = potential difference/Current = [ML2T-3A-1]/[A] = [ML2T-3A-2] Dimensional formula of CR
= [M-1L-2T4A2] [ML2T-3A-2] = [T]
As the (CR) has dimensions of time and so is called time constant of CR …
Is Young’s modulus a dimensionless quantity?
It is a
dimensionless quantity
. So, the units of young’s modulus will be the same as that of stress developed.
