Speed of sound
Why sound travels faster in humid air than normal air as humid air is denser than normal air? (Akash asked)
Answer:
The speed of sound in a medium is inversely proportional to the square root of its density. Humid air is less dense than dry air. Therefore the speed of sounf in humid air is greater than that in dry air.
Confused?
Are you thinking why dry air is more than that of humid air? This is a common misconception. Students used to think that humid air is denser than dry air. But it is not so. Just like skimmed milk (milk removed off its cream) is more dense than normal milk (with cream). Density of cream is much less than that of the rest of milk. So when it is removed, the residual milk becomes denser.
Humid air contains water vapor content. Water vapor is lighter than air. So when air contains water vapor, its density is less. When the water content is removed, it becomes denser.
For more details refer:
Categories: Answers, CBSE Tags: acoustics, answer, Auto, density, Draft, humid air, lighter than air, medium, root, sound, speed, square root, water, water content, water vapor content
Dimensions and conversion of units
The height of mercury column in a barometer in a Calcutta laboratory was recorded to be 75 cm. Calculate this pressure in SI and CGS units using the following data : specific gravity is 13.6, density of water is 1000 kg/m3, g is 9.8 m/s2 at Calcutta. Pressure = hρg in usual symbols Your email:
Categories: Ask Physics, Project Tags: cgs units, conversion, conversion of units, data, density, density of water, mercury column, Physics, pressure, specific gravity, water
Current electricity – Numerical
A 10m length of aluminium wire has a diameter of 1.5mm. It carries a current of 12A. Find (i) the current density. (ii) the drift velocity (iii) the electric field in the wire. aluminium has approximately 10^29 free electrons per m^3
Categories: Ask Physics Tags: aluminium wire, current density, current electricity, density, diameter, drift velocity, field, free electrons, numerical, wire
A numerical problem on Drift velocity
Two conducting wires X and Y of same diameter but different materials are joined in series across a battery . if the number density of electrons in X is twice that in Y . Find the ratio of drift velocity of electrons in the two wires. (Adithya Singh asked this) Incoming search terms:i want to [...]
Categories: Ask Physics Tags: density, diameter, different materials, drift velocity, electrons, number, number density, numerical problem, problem, series
Dimensional Analysis – A solved example
Deduce the dimensional formula for workdone,pressure and density. [posted by boineelo ] Answer: workdone We know that workdone = force x distance Therefore [work done] = [force] [distance] but force = ma [force]=[m][a] [a]=[velocity]/[t] [velocity]=[displacement]/[t] So, putting all these together [work done]=[m][distance][distance]/[time][time] [work done]=ML2T-2 Similarly, you can work out the dimensional formula for pressure and density as [pressure]=[force]/[area]=ML-1T-2 [...]
Categories: Ask Physics Tags: answer, density, density mass, dimensional, dimensional analysis, mass volume, pressure, time time, velocity displacement, work
Explanation For Empirical Horopter: Density Of Photoreceptors
Karolis asks: ” External SiteLink -In this website (and in many more) in page 5, it’s written that photoreceptors are more densely packed in nasal areas of retina than temporal. That’s one of the explanations why empirical horopter (that’s the unit of all points in visual field, that are seen in the same position monocularly) [...]
Categories: Ask Physics Tags: binocular vision, density, nasal, nasal retina, Photoreceptors, Photoreceptors, position, retinas, reverse situation, sitelink, website
