A circular pipe of radius 7 cm is used for water flow transmission. This pipe is moulded into another pipe with a square cross-section keeping the length same. (Ignore the thickness of the pipe). Calculate the hydraulic diameter of the moulded pipe. (Take π = 22/7).

The Reynolds number is found out for a flow in a circular pipe. This circular pipe is moulded into a square pipe, keeping length of the pipe same. Ignore the thickness of the pipe. The Reynolds number changes by __________

A

57% decrease

B

57% increase

C

43% decrease

D

43% increase

The velocity of a fluid in a pipe of diameter D is V. The pipe is connected to another pipe of diameter 2D. Reynolds number in the pipe of diameter D in relation to the pipe of diameter 2D is

A

Double

B

Four times

C

Half

D

Same

Given are the steps to draw a perpendicular to a line at a point within the line when the point is near the centre of line. Arrange the steps. Let AB be the line and P be the point in it i. Join F and P which is perpendicular to AB. ii. Now C as centre take the same radius and cut the arc at D and again D as centre with same radius cut the arc further at E. iii. With centre as P take any radius and draw an arc (more than a semicircle) cuts AB at C. iv. Now D, E as centre take radius (more than half of DE) draw arcs which cut at F.

A

i, iv, ii, iii

B

iii, ii, iv, i

C

iv, iii, i, ii

D

ii, i, iv, iii

The length of each side of square A is increased by 100 percent to make square B. Again the length of each side of square B is increased by 50 percent to make square C. By what percent is the area of square C greater than the sum of the areas of square A and B?

A

75%

B

80%

C

85%

D

90%

The following data pertains to a hollow cylinder and a hollow sphere made of same material and having the same temperature drop over the wall thickness Inside radius = 0.1 m and outside surface area = 1 square meter If the outside radius for both the geometrics is same, calculate the ratio of heat flow in the cylinder to that of sphere?

A

0.056

B

2.345

C

1.756

D

3.543

Consider we have a Double Pipe Heat Exchanger, with the inner tube of Outer diameter 20mm (thickness 2mm) and outer tube of inner diameter 30mm. We have two fluids A & B, we desire to have their flow rates as 15Kg/s and 21Kg/s respectively. What is the value of Hydraulic diameter for the annulus tube?

A

20mm

B

15mm

C

25mm

D

10mm

The length of each of square A is increased by 100 percent to make square B.Again the length of the each side of square B is increased by 50 peacent to make square C.By of the area df square A and B?

A

75%

B

80%

C

85%

D

90%

A square hole is punched out of a circular lamina, the diagonal of the square being the radius of the circle. If ‘r’ is the radius of the circle, the C.G. of the remainder from the corner of the square on the circumference will be

A

$$\frac{{{\text{r}}\left( {\pi + 0.25} \right)}}{{\pi - 0.5}}$$

B

$$\frac{{{\text{r}}\left( {\pi - 0.5} \right)}}{{\pi + 0.25}}$$

C

$$\frac{{{\text{r}}\left( {\pi - 0.25} \right)}}{{\pi - 0.5}}$$

D

$$\frac{{{\text{r}}\left( {\pi + 0.25} \right)}}{{\pi + 0.5}}$$

A steel pipe of 20 mm inner diameter and 2 mm thickness is covered with 20 mm thick of fiber glass insulation (k = 0.05 W/m degree). If the inside and outside convective coefficients are 10 W/m2 degree and 5 W/m2 degree, calculate the overall heat transfer coefficient based on inside diameter of pipe. In the diagram, the diameter of small circle is 20 mm

A

1.789 W/m2 degree

B

2.789 W/m2 degree

C

3.789 W/m2 degree

D

4.789 W/m2 degree

Symmetrical hollow parts of circular crosssection are made by

A

Spinning

B

Drawing

C

Piercing

D

yielding