Home
Class 11
PHYSICS
A rain drop with radus 1.5 mm falls from...

A rain drop with radus 1.5 mm falls from a cloud at a height 1200 m from ground . The density of water is 1000 `kg//m^(3)` and density of air is `1.2 kg//m^(3)`. Assume the drop was spherical throughout the fall and there is no air drag. The impact speed of the drop will be :

A

`14.4 ms^(-1)`

B

`43.56 ms^(-1)`

C

`250 . 6 ms^(-1)`

D

`4.94 ms^(-1)`

Text Solution

Verified by Experts

The correct Answer is:
D

`F_(v) = Mg`
`6 pi eta RV_(T) = ((4)/(3) pi R^(3)) rho_(w) xx g`
`V_(T) = (2 R^(2) rho _(w) g)/( 9 xx eta) = ( 2 xx ( 2 xx 10^(-4))^(2) xx 1000 xx 10 )/(9 xx 1.8 xx 10^(-5))`
= 4.94 m//s
Promotional Banner

Similar Questions

Explore conceptually related problems

The density of air is 1.293 kg m^3 . Express it in cgs units.

A raindrop with radius R = 0.2 mm falls from a cloud at a height h = 2000 m above the ground. Assume that the drop is spherical throughout its fall and the force of buoyance may be neglected, then the terminal speed attained by the raindrop is : [Density of water f_(w)=1000" kg m"^(-3) and Density of air f_(a)=1.2" kg m"^(-3),h=10" m/s"^(2) Coefficient of viscosity of air =1.8xx10^(-5)" Nsm"^(-2) ]

Given the density of air is 1.29 kg m^(-3) . Then, the relative density of air is ________.

Calculate the depth of water at which a bubble of air would just float. Density of water =1000 kg^(-3) and density of air = 1.29 kg ^(-3) . Atmospheric pressure = 10^(5) pa.

A rain drop of radius 0.3 mm falls through air with a terminal velocity of 1 m/s. The viscosity of air is 18 xx 10^(-6) N-s //m^(2) . Find the viscous force on the rain drop.

A small drop of water falls from rest through a large height h in air, the final velocity is

A raindrop of radius 0.2 mm falls through air: If the viscosity of air is 18 xx 10^(-6) Pl, find the viscous drag acting on the drop when its speed is 1 m s^(-1) .