Answer:
Given:
Thermal Kinetic Energy of an electron, 
= Boltzmann's constant
Temperature, T = 1800 K
Solution:
Now, to calculate the de-Broglie wavelength of the electron,
:

(1)
where
h = Planck's constant = 
= momentum of an electron
= velocity of an electron
= mass of electon
Now,
Kinetic energy of an electron = thermal kinetic energy



(2)
Using eqn (2) in (1):

Now, to calculate the de-Broglie wavelength of proton,
:

(3)
where
= mass of proton
= velocity of an proton
Now,
Kinetic energy of a proton = thermal kinetic energy



(4)
Using eqn (4) in (3):

B verifying is the answer
Wouldn't you just have to multiply 220 by 1,000,000? That would mean there are 220,000,000 water droplets in one cubic of the cloud.
Answer:
v = 83.1 % of speed of light
Explanation:
given,
T_e is the earth time = 2.7 s
T_s is the ship time = 1.5 s
we know,

where c is the speed of light
v is the speed of the rock star moving



squaring both side


v = 0.831 c
v = 83.1 % of speed of light