Answer
(a) $\lambda = 4.14~\mu m$ (infrared)
(b) $\lambda = 414~ nm$ (visible light)
(c) $\lambda = 41.4~ nm$ (ultraviolet)
Work Step by Step
(a) We can find the wavelength:
$\lambda = \frac{h~c}{E}$
$\lambda = \frac{(6.626\times 10^{-34}~J~s)(3.0\times 10^8~m/s)}{(0.30~eV)(1.6\times 10^{-19}~J/eV)}$
$\lambda = 4.14\times 10^{-6}~m$
$\lambda = 4.14~\mu m$
According to the diagram of the electromagnetic spectrum, this wavelength is infrared light.
(b) We can find the wavelength:
$\lambda = \frac{h~c}{E}$
$\lambda = \frac{(6.626\times 10^{-34}~J~s)(3.0\times 10^8~m/s)}{(3.0~eV)(1.6\times 10^{-19}~J/eV)}$
$\lambda = 4.14\times 10^{-7}~m$
$\lambda = 414~ nm$
According to the diagram of the electromagnetic spectrum, this wavelength is visible light.
(c) We can find the wavelength:
$\lambda = \frac{h~c}{E}$
$\lambda = \frac{(6.626\times 10^{-34}~J~s)(3.0\times 10^8~m/s)}{(30~eV)(1.6\times 10^{-19}~J/eV)}$
$\lambda = 4.14\times 10^{-8}~m$
$\lambda = 41.4~ nm$
According to the diagram of the electromagnetic spectrum, this wavelength is ultraviolet light.