Question

When an ultraviolet photon is absorbed by a molecule of DNA, the photon's energy can be converted into vibrational energy of the molecular bonds. Excessive vibration damages the molecule by causing the bonds to break. Ultraviolet light of wavelength less than 290 nmnm causes significant damage to DNA; ultraviolet light of longer wavelength causes minimal damage.What is the threshold photon energy, in eV, for DNA damage?

Answer 1

4.28405172412 eV

Step-by-step explanation:

c = Speed of light =
`3* 10^8\ m/s`

h = Planck's constant =
`6.626* 10^(-34)\ m^2kg/s`

`\lambda` = Wavelength = 290 nm

Energy is given by

`E=h(c)/(\lambda)\\\Rightarrow E=6.626* 10^(-34)* (3* 10^(8))/(290* 10^(-9))\\\Rightarrow E=6.8544827586* 10^(-19)\ J`

Converting to eV

`(6.8544827586* 10^(-19))/(1.6* 10^(-19))=4.28405172412\ eV`

The threshold energy is 4.28405172412 eV