By wave particle  duality.
Wavelength , λ = h / mv
where h = Planck's constant = 6.63 * 10⁻³⁴ Js,  m = mass in kg,  v = velocity in m/s.
m = 1kg,  v = 4.5 m/s
λ = h / mv
λ = (6.63 * 10⁻³⁴) /(1*4.5)
λ ≈  1.473 * 10⁻³⁴  m
Option D.
        
             
        
        
        
Answer: The answer is D: 300,000km/s
Explanation:
 
        
             
        
        
        
Answer:
Albert Einstein
Explanation:
 He first predicted the existence of black holes in 1916
 
        
             
        
        
        
Answer:
She will use one 2 as a subscript.
Explanation:
Nitrogen is a chemical element with the symbol "N" and has an atomic number of 7. Thus, it is found in group (5) of the periodic table and as such it has 5 electrons in its outermost shell. Therefore, nitrogen has two (5) valence electrons.
On the other hand, oxygen has an atomic number of 8 and with the symbol "O." 
When nitrogen and oxygen react chemically, they produce a compound known as nitrogen dioxide  
 
In this scenario, Jenny is studying a compound that has two oxygen atoms and one nitrogen atom. Therefore, the statement which describes the subscripts she will use to write the chemical formula is, she will use one 2 as a subscript.

Where: 2 represents the subscript of oxygen.