Mechanical Properties of Fluids MHT-CET pyq's

MHT-CET 2004

 1. If the surface of a liquid is plane, then the angle of contact of the liquid with the walls of container is

• (A) acute angle
• (B) obtuse angle
• (C) 90°
• (D) 0°

MHT-CET 2005

2.  For a liquid which is rising in a capillary, the angle of contact is

• (A) obtuse
• (B) 180°
• (C) acute
• (D) 90°

3. Work done in forming a liquid drop of radius R is W1 and that of radius 3R is W2. The ratio of work done is

• (A) 1 : 3
• (B) 1 : 2
• (C) 1 : 4
• (D) 1 : 9

MHT-CET 2008

 4.  The potential energy of a molecule on the surface of a liquid compared to one inside the liquid is

• (A) zero
• (B) lesser
• (C) equal
• (D) greater

MHT-CET 2010

5. On the surface of the liquid in equilibrium, molecules of the liquid possess

• (A) maximum potential energy
• (B) minimum potential energy
• (C) maximum kinetic energy
• (D) minimum kinetic energy

6. With an increase in temperature, surface tension of liquid (except molten copper and cadmium)

• (A) increases 
• (B) remain same
• (C) decreases 
• (D) first decreases. then increases 

MHT-CET 2011

7. The wettability of a surface by a liquid depends primarily on 

• (A) viscosity 
• (B) surface tension 
• (C) density 
• (D) angle of contact between the surface and the liquid 

MHT-CET 2014 

8. In air, a charged soap bubble of radius 'r' is in equilibrium having outside and inside pressures being equal. The charge on the drop is (∈₀ = permittivity of free space, T = surface tension of soap solution)

• (A) 4Πr²√(2T∈₀ /r)
• (B) 4Πr²√(4T∈₀ /r)
• (C) 4Πr²√(6T∈₀ /r)
• (D) 4Πr²√(8T∈₀ /r)

MHT-CET 2015

9. A liquid rises to a height of 1.8 cm in a glass capillary 'A'. Another glass capillary 'B' having diameter 90% of capillary 'A' is immersed in the same liquid The rise of liquid in capillary 'B' is 

• (A) 1.4 cm 
• (B) 1.8 cm 
• (C) 2.0 cm 
• (D) 2.2 cm

10. A large number of liquid drops each of radius 'a' arc merged to form a single spherical drop of radius 'b'. The energy released in the process is converted into kinetic energy of the big drop formed. The speed of the big drop is

 σ = density of liquid, T = surface tension of liquid

• (A) [6T/⍴(1/a - 1/b)]^1/2
• (B) [6T/⍴(1/b - 1/a)]^1/2
• (C)  [⍴/6T(1/a - 1/b)]^1/2
• (D)  [⍴/6T(1/b - 1/a)]^1/2

MHT-CET 2016

11. In a capillary tube of radius 'R', a straight thin metal wire of radius 'r' (R > r) is inserted symmetrically and one end of the combination is dipped vertically in water such that the lower end of the combination is at same level. The rise of water in the capillary tube is 

T = surface tension of water,  ⍴ = density of water, g = gravitational acceleration

• (A) T/(R + r)⍴g
• (B) R⍴g/2T
• (C) 2T/(R - r)⍴g
• (D) (R - r)⍴g/T

12. A liquid drop having surface energy 'E' is spread into 512 droplets of same size. The final surface energy of the droplets is

• (A) 2E
• (B) 4E 
• (C) 8E
• (D) 12E

MHT-CET 2017

13. When one end of the capillary is dipped in water, the height of water column is 'h'. The upward fora of 105 dyne due to surface tension is balanced by the force due to the weight of water column. The inner circumference of the capillary is (Surface tension of water 7 x 10^-2 N/m)

• (A) 1.5 cm 
• (B) 2  cm
• (C) 2.5 cm 
• (D) 3 cm

14. A big water drop is formed by the combination of  'n' small water drops of equal radii. The ratio of the surface energy of 'n' drops to the surface energy of big drop is 

• (A) n² : 1
• (B) n : 1
• (C) √n : 1
• (D)   : 1 

MHT-CET 2018

15. A metal wire of density '⍴' floats on water surface horizontally. If it is NOT to sink in water then maximum radius of wire is proportional to (T = surface tension of water, g =gravitational acceleration)

• (A) √T/π⍴g
• (B) √π⍴g/T
• (C) T/π⍴g
• (D) π⍴g/T

16. In a capillary tube having area of cross-section 'A', water rises o a height 'h'. If cross-sectional area is reduced to 'A'/9, the rise of water in the capillary tube is

• (A) 4h
• (B) 3h
• (C) 2h
• (D) h

17. A vessel completely filled with water has holes 'A' and 'B' at depths 'h' and '3h' from the top respectively. Hole 'A' is a square of side 'L' and 'B''' is a circle of radius 'r'. The water flowing out per second from both the holes is same. Then 'L' is equal to

• (A) r^1/2 (π)^1/2 3^1/2
• (B) r (π)^1/4 3^1/4
• (C) r (π)^1/2 3^1/4
• (D) r^1/2 (π)^1/3 3^1/2

MHT-CET 2019

18. A metal sphere of radius 'R' and density 'ρ1' is dropped in a liquid of density 'σ' moves with terminal velocity 'V'. Another metal sphere of same radius and density 'ρ2' is dropped in the same liquid, its terminal velocity will be

• (A) V (ρ2 - σ)/(ρ1 - σ)
• (B) V (ρ2 + σ)/(ρ1 + σ)
• (C) V (ρ1 + σ)/(ρ2 + σ)
• (D) V (ρ1 - σ)/(ρ2 - σ)