What is the work function of aluminium metal in kj/mol if light with = 290 nm is necessary to eject electrons?

Work function = hf0, where f is the frequency and h is the plank's constant,
but, f =  c/λ , where c is the speed of light 2.998 ×10^8 m/s, and λ is the wavelength (290 nm) or 2.9 ×10^-7 M
Thus, f = (2.998 ×10^8)/(2.9×10^-7)
           = 1.034 ×10^15 Hz
Therefore, Work function = (1.034×10^15)×(6.626 ×10^-34)
                                        = 6.8513 × 10^-19 Joules 
But, 1 mole = 6.022 ×10^23 particles
Therefore, 6.8513 ×10^-19 × 6.022×10^23
                = 41.259 ×10^4 J/mol
but, 1 kJ = 1000 J
Therefore; 4.1259 ×10^2 kJ/mol

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