Answer:
B. Composed of molecules relatively far apart.
Explanation:
The gas we call "air" has molecules that are relatively far apart.
Answer:

Explanation:
Using the expression for the photoelectric effect as:

Also, 

Applying the equation as:

Where,
h is Plank's constant having value 
c is the speed of light having value 
is the wavelength of the light being bombarded
Given, 
is the binding energy or threshold energy
is the kinetic energy of the electron emitted. = 
Thus, applying values as:





The Curies discovered radium
25*5= 225 and 7hs hsueuxn udneicj
Answer:
It indicates the number 4
Explanation:
IV=4