Answer:
I Think its ABC
Explanation:
No air is the lightest
Helium is lighter than regular air that's why it goes up so then the regular air would be heaviest.
Answer:
The speed of the resistive force is 42.426 m/s
Explanation:
Given;
mass of skydiver, m = 75 kg
terminal velocity, 
The resistive force on the skydiver is known as drag force.
Drag force is directly proportional to square of terminal velocity.

Where;
k is a constant

When the new drag force is half of the original drag force;

Therefore, the speed of the resistive force is 42.426 m/s
Answer:
The wavelength of the emitted radiation is inversely proportional to its frequency, or λ = c/ν. The value of Planck's constant is defined as 6.62607015 × 10−34 joule∙second.
Explanation:
Planck's quantum theory. According to Planck's quantum theory, Different atoms and molecules can emit or absorb energy in discrete quantities only. The smallest amount of energy that can be emitted or absorbed in the form of electromagnetic radiation is known as quantum.
Hope this helps!
Answer:
The electric potential will be "259.695 volt".
Explanation:
In the given question, the figure is not provided. Below is the attached figure given.
Given:





Now,
At point P, the electric potential will be:
⇒ 
By putting values, we get
⇒ ![=9\times 10^9 [\frac{6.39\times 10^{-9}}{0.40} +\frac{3.22\times 10^{-9}}{0.25} ]](https://tex.z-dn.net/?f=%3D9%5Ctimes%2010%5E9%20%5B%5Cfrac%7B6.39%5Ctimes%2010%5E%7B-9%7D%7D%7B0.40%7D%20%2B%5Cfrac%7B3.22%5Ctimes%2010%5E%7B-9%7D%7D%7B0.25%7D%20%5D)
⇒ 