Surface Energy and Surface Tension (Angle of Contact, Excess of Pressure Across a Curved Surface, Application of Surface Tension - Drops, Bubbles, and Capillary Rise...) NEET Questions

Physics - Properties of Solids and Liquids

Surface Energy and Surface Tension (Angle of Contact, Excess of Pressure Across a Curved Surface, Application of Surface Tension - Drops, Bubbles, and Capillary Rise...) MCQ Questions


1.
Surface tension is defined as:
A.
Pressure difference across a curved surface
B.
Energy per unit volume
C.
Force per unit volume of liquid
D.
Force per unit length acting in the plane of the liquid surface
😑 View Answer Rough Work Error
ANSWER :
D. Force per unit length acting in the plane of the liquid surface
2.
The SI unit of surface tension is:
A.
N m
B.
N m⁻¹ (or J m⁻²)
C.
kg m⁻²
D.
Pa m
😑 View Answer Rough Work Error
ANSWER :
B. N m⁻¹ (or J m⁻²)
3.
Surface energy arises because molecules at the surface of a liquid:
A.
Have zero kinetic energy
B.
Are surrounded only on the lower half — have fewer neighbours, so have higher potential energy than interior molecules
C.
Experience attraction from all surrounding molecules equally
D.
Have greater kinetic energy than interior molecules
😑 View Answer Rough Work Error
ANSWER :
B. Are surrounded only on the lower half — have fewer neighbours, so have higher potential energy than interior molecules
4.
In NCERT's stretched film experiment, a bar of length l is moved by distance d on a liquid film. The work done against the surface tension force is:
A.
W = 2 × S × l × d (factor 2 for two surfaces of film)
B.
W = S × l² × d
C.
W = S × l × d
D.
W = S/(l × d)
😑 View Answer Rough Work Error
ANSWER :
A. W = 2 × S × l × d (factor 2 for two surfaces of film)
5.
Surface tension of a liquid generally ___ with increasing temperature:
A.
First increases then decreases
B.
Increases
C.
Decreases
D.
Remains constant
😑 View Answer Rough Work Error
ANSWER :
B. Increases
6.
From NCERT Table 9.3, the surface tension of water at 20°C is approximately:
A.
7.27 N/m
B.
0.0073 N/m
C.
0.727 N/m
D.
0.0727 N/m
😑 View Answer Rough Work Error
ANSWER :
D. 0.0727 N/m