The thermal conductivity in S.I. units is expressed as

1.  J/m2 K

2.  W/mK

3.  W/m K sec

4.  W/m2

View Answer  
4
Correct Answer :

W/mK


Explanation :
No Explanation available for this question

Two blocks with masses M and m are in contact with each other and are resting on a horizontal frictionless floor. When horizontal force is applied to the heavier, the blocks accelerate to the right. The force between the two blocks is

1.  (M+m)F/m

2.  MF/m

3.  mF/M

4.  mF/(M+m)

View Answer  
4
Correct Answer :

mF/(M+m)


Explanation :
No Explanation available for this question

Coefficient of thermal conductivity is defined as the heat flow per unit time

1.  Through unit thickness

2.  When temperature difference of unity is maintained between opposite faces

3.  When temperature gradient is unity

4.  Across unit area when temperature gradient is unity

View Answer  
4
Correct Answer :

When temperature gradient is unity


Explanation :
No Explanation available for this question

Find efficiency deals with

1.  Thermal performance

2.  Economical material requirement

3.  Cost of manufacturing

4.  All of these

View Answer  
4
Correct Answer :

Thermal performance


Explanation :
No Explanation available for this question

A particle starts from rest with a constant acceleration α m/sec2 and after some time it deaccelerates at a uniform rate of β m/sec2 till it comes to rest. If the total time taken between two rests position is t, then maximum velocity acquired by the particular would be

1.  (α+β/2)t

2.  (α-β/2)t

3.  (αβ/ α+β)t

4.  (α+β/α-β)t

View Answer  
4
Correct Answer :

(αβ/ α+β)t


Explanation :
No Explanation available for this question

The overall heat transfer coefficient (U) for a composite wall of thickness x1, x2, x3 and of corresponding thermal conductivities k1, k2, k3 is given by equation

1.  1/U = (k1/x1) + (k2/x2) + (k3/x3)

2.  U = (k1/x1) + (k2/x2) + (k3/x3)

3.  1/U = (x1/k1) + (x2/k2) + (x3/k3)

4.  U = (x1/k1) + (x2/k2) + (x3/k3)

View Answer  
4
Correct Answer :

1/U = (x1/k1) + (x2/k2) + (x3/k3)


Explanation :
No Explanation available for this question

A composite wall of two layers of thickness x1, ? x2 and of thermal conductivities k1 and k2 is having cross-sectional area a normal to the path of heat flow. If the wall surface temperatures are T1 and T3, then rate of heat flow (Q) is equal to

1.  A (T1 – T3)/[(x1/k2) + (?x2/k1)]

2.  A k1k2 (T1 – T3)/ (?x1 + ?x2)

3.  (Ak1 + Ak2) (T1 – T3)/ (?x1 + ?x2)

4.  (T1 – T3)/ [(?x1/Ak1) + (?x2/?k2)]

View Answer  
4
Correct Answer :

A (T1 – T3)/[(x1/k2) + (?x2/k1)]


Explanation :
No Explanation available for this question

In a future the wall thickness is 60 cm and is 100 wide and 150 cm high of material with thermal conductivity 0.4 W/mK. The temperature inside and outside are 10000 and 40 C respectively. The thermal resistance is

1.  1 k/W

2.  2 k/W

3.  18 k/W

4.  15 k/W

View Answer  
4
Correct Answer :

1 k/W


Explanation :
No Explanation available for this question

Three metal walls of the same cross-sectional area having thermal conductivities in the ratio 1: 2: 4 transfer heat at the rate of 6000 kJ/hr. For the same wall thickness, the temperature drops will be in the ratio

1.  1: 2: 4

2.  1: 1/2: 1/4

3.  1/4: 1/2: 1

4.  1: 1: 1

View Answer  
4
Correct Answer :

1: 1/2: 1/4


Explanation :
No Explanation available for this question

A train travels between two stations 15 km apart in 18 minutes .If the train accelerates for a part of journey uniformly followed by uniform retardation, the maximum speed retained by the train during the journey will be

1.  60 km/hr

2.  80 km/hr

3.  100 km/hr

4.  125 km/hr

View Answer  
4
Correct Answer :

100 km/hr


Explanation :
No Explanation available for this question
Previous Next

Interview Questions

MongoDB
Java Script
Node JS
PHP
JQuery
Python