Mechanical Properties of Fluids · Question 10

Sixty four raindrops of radius 1 mm each falling down with a terminal velocity of 10 cm/s coalesce to form a bigger drop. The terminal velocity of bigger drop is cm/s.

A cubical block of density b = 600 kg/m3 floats in a liquid of density l = 900 kg/m3. If the height of block is H = 8.0 cm, then height of the submerged part is cm.

1. 6.3
2. 4.3
3. 7.3
4. 5.3

A soap bubble of surface tension 0.04 N/m is blown to a diameter of 7 cm. If (15000 - x) of work is done in blowing it further to make its diameter 14 cm, then the value of x is . ( = 22/7)

A small metallic sphere of diameter 2 mm and density 10.5 g/cm3 is dropped in glycerine having viscosity 10 Poise and density 1.5 g/cm3 respectively. The terminal velocity attained by the sphere is cm/s. ( = 227 and g = 10 m/s2)

1. 1.0
2. 1.5
3. 3.0
4. 2.0

A cylindrical tube AB of length l, closed at both ends contains an ideal gas of 1 mol having molecular weight M. The tube is rotated in a horizontal plane with constant angular velocity about an axis perpendicular to AB and passing through the edge at end A, as shown in the figure. If PA and PB are the pressures at A and B respectively, then (Consider the temperature is same at all points in the tube) [figure]

1. PB = PA e ( M 2 l23RT )
2. PB = PA
3. PB = PA e ( M 2 l22RT )
4. PB = PA e ( M 2 l2RT )

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below

1. Statement I is false but Statement II is true
2. Statement I is true but Statement II is false
3. Both Statement I and Statement II are false
4. Both Statement I and Statement II are true

When a part of a straight capillary tube is placed vertically in a liquid, the liquid rises up to certain height h. If the inner radius of the capillary tube, density of the liquid and surface tension of the liquid decrease by 1% each, then the height of the liquid in the tube will change by %.

1. +3
2. +1
3. -1
4. -3

Water flows through a horizontal tube as shown in the figure. The difference in height between the water columns in vertical tubes is 5 cm and the area of cross-sections at A and B are 6 cm2 and 3 cm2 respectively. The rate of flow will be cm3/s. (take g = 10 m/s2) [figure]

1. 100 3
2. 200 3
3. 200 6
4. 200 3

Surface tension of two liquids (having same densities), T1 and T2, are measured using capillary rise method utilizing two tubes with inner radii of r1 and r2 where r1 > r2. The measured liquid heights in these tubes are h1 and h2 respectively. [Ignore the weight of the liquid above the lowest point of meniscus]. The heights h1 and h2 and surface tensions T1 and T2 satisfy the relation :

1. h1 > h2 and T1 = T2
2. h1 < h2 and T1 = T2
3. h1 > h2 and T1 < T2
4. h1 = h2 and T1 = T2

The terminal velocity of a metallic ball of radius 6 mm in a viscous fluid is 20 cm/s. The terminal velocity of another ball of same material and having radius 3 mm in the same fluid will be cm/s.