Problem $9$:$$ The wavelength range of visible light is usually taken to be from $400$ to $700$ nm$,$ although it can vary from person to person.

Part $($a$)$ Calculate the ratio of the highest to lowest frequency of electromagnetic waves that most us can see.

Numeric$$: A numeric value is expected and not an expression.

fmax$/$fmin $=\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$

Part $($b$)$ For comparison, calculate the ratio of the highest to lowest frequency the ear can hear. This range is usually taken to be from $20$ kHz to $20$ Hz$.$

Numeric$$: A numeric value is expected and not an expression.

fmax$/$fmin $=\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$