Your answer is C) The year the element was discovered :)
 
        
                    
             
        
        
        
Answer:
demand (an amount) as a price for a service rendered or goods supplied.
Explanation:
 to enter or record as an obligation against a person or his account.  to accuse or impute a fault to (a person, etc), as formally in a court of law. to command; place a burden upon or assign responsibility toI was charged to take the message to headquarters.
 
        
                    
             
        
        
        
Answer: 18.27°
Explanation:
Given 
Index of refraction of blue light, n(b) = 1.64
Wavelength of blue light, λ(b) = 440 nm
Index of refraction of red light, n(r) = 1.595
Wavelength of red light, λ(r) = 670 nm
Angle of incident, θ = 30°
Angle of refraction of red light is
θ(r) = sin^-1 [(n(a)* sin θ) / n(r)], where n(a) = index of refraction of air = 1
So that, 
θ(r) = sin^-1 [(1 * sin 30) / 1.595]
θ(r) = sin^-1 (0.5 / 1.595)
θ(r) = sin^-1 0.3135
θ(r) = 18.27°
 
        
             
        
        
        
Energy cannot be created nor be destroyed