Since a mole represents a large number of molecules, it is not possible to count the number of molecules directly, the only method is through weight. The mass is converted to moles so that the number of molecules in the reaction are kept track of.
Answer:
green light have high energy
Explanation:
We have given the wavelength of the red light 
Speed of the light 
The energy of the signal is given by 
The frequency of the green light is given by:
So energy 
So green light have high energy
Answer: 
It is given that:
Density of material =ρ
radius of inner spherical shell = 
radius of outer spherical shell=
we know that the volume of sphere is 
Volume of the given spherical shell = 
Then mass of the spherical shell can be calculate as:
Mass, m=density/ volume
The so-called "velocity-time" graph is actually a "speed-time" graph. At any point
on it, the 'x'-coordinate is a time, and the 'y'-coordinate is the speed at that time.
'Velocity' is a speed AND a direction. Without a direction, you do not have a velocity,
and these graphs never show the direction of the motion. It seems to me that it would be
pretty tough to draw a graph that shows the direction of motion at every instant of time,
so my take is that you'll never see a true "velocity-time" graph.
At best, it would need a second line on it, whose 'y'-coordinate referred to a second
axis, calibrated in angle and representing the 'bearing' or 'heading' of the motion at
each instant. The graph of uniform circular motion, for example, would have a straight
horizontal line for speed, and a 'sawtooth' wave for direction.
