Advertisements
Advertisements
प्रश्न
Solve the previous problem if the lead piece is fastened on the top surface of the block and the block is to float with its upper surface just dipping into water.
Advertisements
उत्तर
Given:
Mass of wood, mw = 200 g
Specific gravity of wood, ρW = 0.8 gm/cc
Specific gravity of lead, ρPB= 11.3 gm/cc
\[\text{ We know: }\]
\[\text{ Mg = w} \]
\[\text{ Thus, we have: } \]
\[( \text{m}_\text{w} + \text{m}_{\text{pb}} )\text{g} = \text{V}_\text{w} \times \rho \times g\] \[ [\rho = \text{ Density of water }]\]
\[ \Rightarrow 200 + \text{m}_{\text{pb}} = \frac{200}{0 . 8} \times 1\]
\[ \Rightarrow \text{m}_{\text{pb}} = 250 - 200 = 50 \text{gm}\]
APPEARS IN
संबंधित प्रश्न
Explain why Water with detergent dissolved in it should have small angles of contact.
In a conical pendulum, a string of length 120 cm is fixed at rigid support and carries a mass
of 150 g at its free end. If the mass is revolved in a horizontal circle of radius 0.2 m around a
vertical axis, calculate tension in the string (g = 9.8 m/s2)
It is said that a liquid rises or is depressed in capillary due to the surface tension. If a liquid neither rises nor depresses in a capillary, can we conclude that the surface tension of the liquid is zero?
If more air is pushed in a soap bubble, the pressure in it
Viscosity is a property of
A cubical block of ice floating in water has to support a metal piece weighing 0.5 kg. Water can be the minimum edge of the block so that it does not sink in water? Specific gravity of ice = 0.9.
A cubical metal block of edge 12 cm floats in mercury with one fifth of the height inside the mercury. Water in it. Find the height of the water column to be poured.
Specific gravity of mercury = 13.6.
How much amount of work is done in forming a soap bubble of radius r?
Calculate the rise of water inside a clean glass capillary tube of radius 0.1 mm, when immersed in water of surface tension 7 × 10-2 N/m. The angle of contact between water and glass is zero, the density of water = 1000 kg/m3, g = 9.8 m/s2.
Obtain an expression for the capillary rise or fall using the forces method.
The property of _______ of a liquid surface enables the water droplets to move upward in plants.
What is capillarity?
Two small drops of mercury each of radius 'R' coalesce to form a large single drop. The ratio of the total surface energies before and after the change is ____________.
The excess of pressure, due to surface tension, on a spherical liquid drop of radius 'R' is proportional to ______.
Why is raindrop spherical in nature?
The sufrace tension and vapour pressure of water at 20°C is 7.28 × 10–2 Nm–1 and 2.33 × 103 Pa, respectively. What is the radius of the smallest spherical water droplet which can form without evaporating at 20°C?
This model of the atmosphere works for relatively small distances. Identify the underlying assumption that limits the model.
Surface tension is exhibited by liquids due to force of attraction between molecules of the liquid. The surface tension decreases with increase in temperature and vanishes at boiling point. Given that the latent heat of vaporisation for water Lv = 540 k cal kg–1, the mechanical equivalent of heat J = 4.2 J cal–1, density of water ρw = 103 kg l–1, Avagadro’s No NA = 6.0 × 1026 k mole–1 and the molecular weight of water MA = 18 kg for 1 k mole.
- Estimate the energy required for one molecule of water to evaporate.
- Show that the inter–molecular distance for water is `d = [M_A/N_A xx 1/ρ_w]^(1/3)` and find its value.
- 1 g of water in the vapor state at 1 atm occupies 1601 cm3. Estimate the intermolecular distance at boiling point, in the vapour state.
- During vaporisation a molecule overcomes a force F, assumed constant, to go from an inter-molecular distance d to d ′. Estimate the value of F.
- Calculate F/d, which is a measure of the surface tension.
Eight droplets of water each of radius 0.2 mm coalesce into a single drop. Find the decrease in the surface area.
A drop of water and a soap bubble have the same radii. Surface tension of soap solution is half of that of water. The ratio of excess pressure inside the drop and bubble is ______.
