Surface tension-Basic

Surface tension-Basic

Dear Readers,

Compared to other sections, Physics is considered to be the most scoring section. If prepared thoroughly, Physics can help students to secure a meritorious position in the exam. These questions are very important in achieving your success in Exams after 12th.

Q1. The spherical shape of rain-drop is due to

•  Density of the liquid
•  Surface tension
•  Atmospheric pressure
•  Gravity

Surface tension

Q2. At which of the following temperatures, the value of surface tension of water is minimum

•  4°C
•  25°C
•  50°C
•  75°C

75°C

Q3. Force necessary to pull a circular plate of 5cm radius from water surface for which surface tension is 75 dynes/cm, is

•  30 dynes
•  60 dynes
•  750 dynes
•  750πdynes

750πdynes

Q4. A square frame of side L is dipped in a liquid. On taking it out, a membrane is formed. If the surface tension of the liquid is T, the force acting on the frame will be

•  2TL
•  4TL
•  8TL
•  10TL

8TL

Q5. Ball pen and fountain pen depend respectively upon the principle of

•  Surface tension and viscosity
•  Surface tension and gravity
•  Gravitation and surface tension
•  Surface tension and surface tension

Gravitation and surface tension

Q6. A water drop of 0.05cm3 is squeezed between two glass plates and spreads into area of 40cm2. If the surface tension of water is 70 dyne/cm then the normal force required to separate the glass plates from each other will be

•  90 N
•  45 N
•  22.5 N
•  450 N

45 N

Q7. The main difference between a stretched membrane and the liquid surface is

•  The liquid surface has a tendency to contract but the stretched membrane does not
•  The surface tension does not depend on area but on the tension of the stretched membrane does
•  The surface tension increases with increases in area
•  Surface tension increases irregularly with temperature

The surface tension does not depend on area but on the tension of the stretched membrane does

Q8. A hollow disc of aluminum whose external and internal radii are R and r respectively, is floating on the surface of a liquid whose surface tension is T. The maximum weight of disc can be

•  2π (R + r) T
•   2π (R – r) T
•  4π (R + r) T
•   4π (R – r) T

2π (R + r) T