Answer:
Explanation:
At the time of a body achieving terminal velocity, the drag force becomes equal to the weight of the body less the buoyant force by the surrounding medium which can be represented by the following equation
Where r is radius of the body , d is density of the material of the body σ is density of the medium and n is coefficient of viscosity of the medium and v is terminal velocity.
Simplifying
v = 
Assuming the value of density of air as 1.225 kg/m³ and putting other given values in the formula we get
v = ![[tex]\frac{2\times (1.2\times10^{-5})^2(2182-1.225)}{9\times 1.8\times10^{-5}}](https://tex.z-dn.net/?f=%5Btex%5D%5Cfrac%7B2%5Ctimes%20%281.2%5Ctimes10%5E%7B-5%7D%29%5E2%282182-1.225%29%7D%7B9%5Ctimes%201.8%5Ctimes10%5E%7B-5%7D%7D)
[/tex]
v = 387 x 10⁻⁵ m/s
Terminal velocity = 387 x 10⁻⁵ m/s
Time taken to fall a distance of 100 m
= 
= 2.6 x 10⁴ s.
Answer:
The new force becomes 4 times the initial force.
Explanation:
The force of attraction or repulsion is given by the relation as follows :
Where
d is the distance between the interacting charges
F is inversely proportional to the distance between charges.
If the distance is halved, d'=(d/2), new force is given by :
So, the new force becomes 4 times the initial force.
Answer:
The order of increasing energy is as follows
"microwave < infrared < visible < ultraviolet"
Option (A) is correct.
Explanation:
Given:
Arrange the following spectral regions in order of increasing energy: infrared, microwave, ultraviolet, visible.
From the formula of energy in terms of frequency.
Where 
planck constant, 
frequency of light.
From above formula we can conclude that higher frequency means higher energy.
In our case ultraviolet has higher frequency and microwave has lower frequency.
So ultraviolet has higher energy and microwave has lower energy.
microwave < infrared < visible < ultraviolet
Therefore, the order of increasing energy is as follows
"microwave < infrared < visible < ultraviolet"
Answer:
option (B)
Explanation:
Intensity of unpolarised light, I = 25 W/m^2
When it passes from first polarisr, the intensity of light becomes
Let the intensity of light as it passes from second polariser is I''.
According to the law of Malus
Where, θ be the angle between the axis first polariser and the second polariser.
I'' = 11.66 W/m^2
I'' = 11.7 W/m^2
85 N - 40 N = 45 N
And depending on direction the greater force is being pulled towards
