In calculating the energy of a photon of light, we need the relationship for energy and the frequency which is expressed as:
 
E=hv 
where h is the Planck's constant (6.626 x 10-34 J s)and v is the frequency.
E = 6.626 x 10-34 J s (<span>7.33 x 10^14 /s) = 4.857 x 10^-19 J</span>
        
             
        
        
        
Answer:
21
Explanation:
21 is x because 211211 1 1 1 1  1aghh
 
        
                    
             
        
        
        
Um student a because they were there a few seconds ahead
        
             
        
        
        
Answer:
The answer is A. Cementing...
Explanation:
hope this helps
 
        
                    
             
        
        
        
There's a very subtle thing going on here, one that could blow your mind.
Wherever we look in the universe, no matter what direction we look, 
we see the light from distant galaxies arriving at our telescopes with 
longer wavelengths than the light SHOULD have.
The only way we know of right now that can cause light waves to get 
longer after they leave the source is motion of the source away from 
the observer. The lengthening of the waves on account of that motion 
is called the Doppler effect.  (The answer to the question is choice-c.)
But that may not be the only way that light waves can get stretched.  It's 
the only way we know of so far, and so we say that the distant galaxies 
are all moving away from us.  
From that, we say the whole universe is expanding, and that right there is 
one of the strongest observations that we explain with the Big Bang theory 
of creation. 
Now:  If ... say tomorrow ... a competent Physicist discovers another way 
for light waves to get stretched after they leave the source, then the whole
"expanding universe" idea is out the window, and probably the Big Bang 
theory along with it !
Now that our mind has been blown, come back down to Earth with me,
and I'll give you something else to think about:
It's true that when we look at distant galaxies, we do see their light
arriving in our telescopes with longer wavelengths than it should have.
And then we use the Doppler effect to calculate how fast that galaxy
is moving away from us.  That's all true.  Astronomers are doing it
every day.                                   I mean every night.
So here's the question for you to think about ... maybe even READ about:
When the light from a distant galaxy pours into our telescope, and we
look at it, and we measure its wavelength, and we find that the wavelength
is longer than it should be ... how do we know what it should be ? ? ?