Answer:
Green light
Explanation:
To solve the problem, we need to evaluate which wavelength of light corresponds to the threshold frequency of the metal
The relationship between frequency and wavelength is:
[tex]\lambda=\frac{c}{f}[/tex]
where
[tex]c=3\cdot 10^8 m/s[/tex] is the speed of light
[tex]f=5.45\cdot 10^{14}Hz[/tex] is the frequency
Substituting into the formula,
[tex]\lambda=\frac{3\cdot 10^8 m/s}{5.45\cdot 10^{14} Hz}=5.50\cdot 10^{-7}m=550 nm[/tex]
And wavelength of 550 nm corresponds to green light.
