Heat Transfer MCQ’s – Dimensional Homogeneity
1 - Question
How is dimensional homogeneity related with fundamental units of measurements?
c) Dependent but can vary
Explanation: This implies that the length dimension can be added to subtract from only a length dimension.
2 - Question
What is the time period of oscillation of a simple pendulum of length L and mass m?
a) 2 π (L/g) 3/2
b) 2 π (L/g)
c) 2 π (L/g) 2
d) 2 π (L/g) 1/2
Explanation: The time period of a simple pendulum means the time it takes for one complete revolution.
3 - Question
The principle of dimensional homogeneity serves the following useful concepts (i) It helps to check whether an equation of any physical phenomenon is dimensionally homogenous or not (ii) It helps to determine the dimensions of a physical quantity (iii) It helps to convert the units from one system to another Identify the correct statements
a) i and ii
b) ii and iii
c) i, ii and iii
d) ii only
Explanation: It serves all the aspects
4 - Question
The equation of friction loss in a pipe of length l and diameter d through which fluid flows with velocity v is
a) h i = 4 f V 2/d g
b) h i = 4 f V 2/d 2 g
c) h i = 4 f V 2/d 2 g
d) h i = 4 f V 2/2 g
Explanation: Here f is any constant with no dimensions whatsoever.
5 - Question
Bernoulli’s equation for fluid flow along a stream line is given as
a) p/w + V 2/2 g + y = 2
b) p/w + V/2 g + y = constant
c) p/w + V 2/2 g + y = 1
d) p/w + V 2/2 g + y = constant
Explanation: This is the Bernoulli’s equation and is dimensionally homogenous.
6 - Question
The convective film coefficient in k cal/m2 hr degree can be converted to J/m2 s degree by multiplying it with a factor
Explanation: Both k cal/m2 hr degree and J/m2 s are the units of convective film coefficient.
7 - Question
The pressure in kg/cm2 can be converted to N/m2 by multiplying it with a factor
a) 9.807 * 10 2
b) 9.807 * 10 3
c) 9.807 * 10 4
d) 9.807 * 10 5
Explanation: Both kg/cm2 and N/m2 are the units of pressure.
8 - Question
How many Newton’s are there in one kg?
Explanation: 1 kg = 9.807 N. Newton is the unit of force and kg is the unit of mass.
9 - Question
How many Joule are there in 1 k cal?
Explanation: 1 k cal = 4186 J. Joule is the unit of work done.
10 - Question
How many fundamental quantities are there?
Explanation: These are M, L and T. M is mass, L is length and T is time.