Question

Is trom surface of Delectromae to ejectelee ragnetic energy required a electrons from surt Tungsten me talis 440 kJ/mol slectromagnetic rad tromagnetie radiation strikes the metal with wav e me tal with wavelength 2oonm a) De termine threshold energy in Jl electron 16) Determine total energy striking tungsten metal. calculate maximum kine. energy observed among erecis

Answer 1

Total energy = threshold energy + kinetic energy

Given, wavelength of light absorbed ($\lambda$) = 200nm

= 200×10^-9 m

= 2×10^-7 m

a)

Threshold energy = 440 KJ/mol

= (440×10³/6.02×10²³)

= 7.31×10^-19 J/electron.

b)

Total energy = h$\frac{c}{\lambda}$

= (6.626×10^-34×3×10⁸/2×10^-7)

= 9.94 ×10^-19 J/electron.

C)

Now, Kinetic energy of each electron

= (9.94×10^-19 - 7.31×10^-19 ) J

= 2.63×10^-19J.