I’m not sure I think if you google it it should pop up or go on quizlet sorry
        
             
        
        
        
Using the formula v=f times lambada
then v=the speed of light. 
and f=what’s we’re looking for
and lambada=the wavelength. 
so then you sub what you have (v and lambada) in the formula. 
then multiply the frequency(f) by the given wavelength and then solve for f
 
        
        
        
 Answer:
The impulse on the object is 60Ns.
Explanation:
Impulse is defined as the product of the force applied on an object and the time at which it acts. It is also the change in the momentum of a body.
F = m a
F = m( )
)
⇒     Ft = m( -
 -  )
)
where: F is the dorce on the object, t is the time at which it acts, m is the mass of the object,  is its initialvelocity and
 is its initialvelocity and  is the final velocity of the object.
 is the final velocity of the object.
Therefore,
 impulse = Ft = m( -
 -  )
)
From the question, m = 3kg,  = 0m/s and
 = 0m/s and  = 20m/s.
 = 20m/s.
So that,
Impulse = 3 (20 - 0)
              = 3(20)
              = 60Ns
The impulse on the object is 60Ns.
 
        
             
        
        
        
Answer: The ratio of atoms of potassium to ratio of atoms of oxygen is 4:2
Explanation: 
According to the law of conservation of mass, mass can neither be created nor be destroyed, and remains conserved. The mass of products must be same as that of the reactants. 
Thus the number of atoms of each element must be same on both sides of the equation so as to keep the mass same and thus balanced chemical equations are written.
K exists as atoms and oxygen exist as molecule which consists of 2 atoms. The ratio of number of atoms on both sides of the reaction are same and thus the ratio of atoms of potassium to ratio of atoms of oxygen is 4:2.
 
        
                    
             
        
        
        
If the substance doesn't change chemically, it is a physical reaction.