Excess pressure & Angle of contact (surface tension)

In this post, we are presenting a few sets of MCQ worksheets with questions on Excess pressure & Angle of contact (both from the Surface Tension chapter of Physics). You can also try our MCQ worksheet on Surface tension concepts and surface energy.

Table Of Contents

Excess pressure – MCQ worksheets
MCQ Problems based on Angle of contact

Excess pressure – MCQ worksheets

25) Two bubbles A and B (A > B) are joined through a narrow tube. Then [UPSEAT 2001; Kerala (Med.) 2002]

(a) The size of A will increase (b) The size of B will increase
(c) The size of B will increase until the pressure equals (d) None of these

26) Excess pressure of one soap bubble is four times more than the other. Then the ratio of the volume of the first bubble to another one is
[CPMT 1997; MH CET 2000]

(a) 1 : 64 (b) 1 : 4 (c) 64 : 1 (d) 1 : 2

27) The pressure of air in a soap bubble of 0.7cm diameter is 8mm of water above the pressure outside. The surface tension of the soap solution is
[MP PET 1991; MP PMT 1997]

(a) 100 dyne/cm (b) 68.66 dyne/cm (c) 137 dyne/cm (d) 150 dyne/cm

28) An air bubble of radius r in water is at a depth h below the water surface at some instant. If P is atmospheric pressure, d and T are density and surface tension of water respectively, the pressure inside the bubble will be [Roorkee 1990]

29) A soap bubble is very slowly blown at the end of a glass tube by a mechanical pump which supplies a fixed volume of air every minute whatever the pressure against which it is pumping. The excess pressure P inside the bubble varies with time as shown by which graph

MCQ Problems based on Angle of contact

30 ) A liquid does not wet the sides of a solid, if the angle of contact is [MP PAT 1990; AFMC 1988, MNR 1998, KCET 1998, Haryana CEE 1998; RPMT 1999; 2003]

(a) Zero (b) Obtuse (More than 90o) (c) Acute (Less than 90o) (d) 90o0

31) The meniscus of mercury in the capillary tube is [MP PET/PMT 1988]

(a) Convex (b) Concave (c) Plane (d) Uncertain

32) The angle of contact between glass and mercury in degree is [MP PMT 1987]

(a) 0 (b) 30 (c) 90 (d) 135

33) When the temperature is increased the angle of contact of a liquid

(a) Increases (b) Decreases (c) Remains the same (d) First increases and then decreases

34) For those liquids which do not wet the solid surface, the ratio of cohesive force and adhesive force will be

35) The waterproofing agent makes an angle of contact

(a) From acute angle to obtuse angle (b) From obtuse angle to acute angle
(c) From obtuse angle to right angle (d) From acute angle to right angle

36) A glass plate is partly dipped vertically in the mercury and the angle of contact is measured. If the plate is inclined, then the angle of contact will

(a) Increase (b) Remain unchanged (c) Increase or decrease (d) Decrease

The solution to MCQ 25 to 36 is available on the next page.

Pages: 1 2