Wavelength of light `(lambda) = 5000Å = 5xx 10^(-7)m`
Work function `(hv_(0)) = 1.9 eV = 1.9 xx 1.6 xx 10^(-19)J = 3.4 xx 10^(-19)J`
a. Energy of photons
`E = hv = (hc)/(lambda)`
`= ((6.626 xx 10^(-34) j S) xx (3 xx 10^(8)m s^(-1)))/(5 xx 10^(-7) m)`
`= 3.97 xx 10^(-19) J`
Kinetic energy of photoelectrons
`KE = (1)/(2) mv^(2)`
`= hv - hv_(0)`
`= (3.97 xx 10^(-19) J)- (3.4 xx 10^(-19) J)`
`= 9.3 xx 10^(-20) J`