For a surface molecule: 1. The net force on it is zero. 2. There is a net downward force. 3. The potential energy is less than that of a molecule inside. 4. The potential energy is more than that of a molecule inside.

For a surface molecule: 1. The net force on it is zero. 2. There …

Download App

Question

For a surface molecule:

The net force on it is zero.
There is a net downward force.
The potential energy is less than that of a molecule inside.
The potential energy is more than that of a molecule inside.

✓

Answer

There is a net downward force.

The potential energy is more than that of a molecule inside.

Explanation:

A molecule viewed from the top to surface of the fluid. Force exerted on a molecule by all nearby molecule are equal and opposite, so net horizontal component of force is zero. as a molecule is viewed horizontally to the surface of fluid a vertically downward force acts on molecule due to which it does not escape from surface.

There is a net attractive force on molecules at surface acting downwards. So the P.E of molecules at the surface is negative to lower ones but in magnitude PE(mgh) is more than that of the lower or inside molecules.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q (1 Marks)" from Mechanical Properties of Fluids→Mechanical Properties of Fluids — all question types→Physics STD 11 Science question papers→Rajasthan Board STD 11 Science question papers→Rajasthan Board question paper generator→

Similar questions

A rubber ball is dropped from a height of $5 \,m$ on a planet where the acceleration due to gravity is not known. On bouncing, it rises to $1.8\, m$. The ball loses its velocity on bouncing by a factor of

→

Two particles of mass $m$ each are tied at the ends of a light string of length $2a$ . The whole system is kept on a frictionless horizontal surface with the string held tight so that each mass is at a distance $'a'$ from the centre $P$ (as shown in the figure). Now, the mid-point of the string is pulled vertically upwards with a small but constant force $F$ . As a result, the particles move towards each other on the surface. The magnitude of acceleration, when the separation between them becomes $2x$ , is

→

A person travels along a straight road for the first half time with a velocity ${v_1}$ and the next half time with a velocity ${v_2}$ . The mean velocity $V$ of the man is

→

The value of restitution coefficient e for perfectly elastic collision is:

→

Two bodies A and B having equal surface areas are maintained at temperatures 10^°C and 20^°C. The thermal radiation emitted in a given time by A and B are in the ratio:

1 : 1.15
1 : 2
1 : 4
1 : 16

→

A cylindrical capillary tube of $0.2 mm$ radius is made by joining two capillaries $T 1$ and $T 2$ of different materials having water contact angles of $0^{\circ}$ and $60^{\circ}$, respectively. The capillary tube is dipped vertically in water in two different configurations, case I and II as shown in figure. Which of the following option($s$) is(are) correct?

(Surface tension of water $=0.075 N / m$, density of water $=1000 kg / m ^3$, take $g =10 m / s ^2$ )

$(1)$ The correction in the height of water column raised in the tube, due to weight of water contained in the meniscus, will be different for both cases.

$(2)$ For case I, if the capillary joint is $5 cm$ above the water surface, the height of water column raised in the tube will be more than $8.75 cm$. (Neglect the weight of the water in the meniscus)

$(3)$ For case $I$, if the joint is kept at $8 cm$ above the water surface, the height of water column in the tube will be $7.5 cm$. (Neglect the weight of the water in the meniscus)

$(4)$ For case II, if the capillary joint is $5 cm$ above the water surface, the height of water column raised in the tube will be $3.75 cm$. (Neglect the weight of the water in the meniscus)