91影视

The expression for frequency of the monochromatic wave is given by,

$f=\frac{c}{位}$

Here, localid="1663053548195" $f$is the frequency, localid="1663053597284" $位$is the wavelength, localid="1663053648806" $c$is the speed of the light.

The expression for energy of the photon is given by,

localid="1663053690989" $E=hf$

Here, localid="1663053732860" $h$is the Planck鈥檚 constant.

Combine the above two equations.

localid="1663053778641" $E=\frac{hc}{位}$

The minimum energy corresponds to the greatest wavelength recorded by the film is given by,

localid="1663053823945" $E_{min}=\frac{hc}{{位}_{greatest}}$

localid="1663053872627" ${位}_{greatest}=\frac{hc}{E_{min}}$ 鈥︹��. (1)

(a)

Substitute $0.6\mathrm{eV}$for $E_{\min },6.626脳{10}^{-34}\mathrm{J}路\mathrm{s}$, for $h$, and $3脳{10}^8$for $c$in equation (1).

$$\begin{gathered} {位}_{\mathrm{greatest}}=\frac{\left(6.626脳{10}^{-34}\mathrm{J}\right)\left(3脳{10}^8\mathrm{m}/\mathrm{s}\right)}{\left(0.6\mathrm{eV}\right)\left({\displaystyle \frac{1.6脳{10}^{-19}\mathrm{J}}{1\mathrm{eV}}}\right)} \\ =2.1脳{10}^{-6}\mathrm{m}\left(\frac{1\mathrm{渭尘}}{{10}^{-6}\mathrm{m}}\right) \\ =2.1\mathrm{渭尘} \end{gathered}$$

Therefore, the greatest wavelength of light that can be recorded by the film is $2.1\mathrm{渭尘}$.

(b)

The infrared region in the electromagnetic spectrum ranges from $0.7\mathrm{渭尘}$to 1mm.

The wavelength $2.1\mathrm{渭尘}$is in the range of $0.7\mathrm{渭尘}$to 1mm. So, the wavelength is located in the infrared region of the electromagnetic spectrum.

Therefore, the region of the electromagnetic spectrum is infrared.