The work function of a metallic surface is `5.01 eV`. The photo - electrons are emitted when light of wavelength `2000 Å` falls on it . The potential difference applied to stop the fastest photo - electrons is `[ h = 4.14 xx 10^(-15) eV sec]`

Options

A. `1.2 "volts"`
B. `2.24 "volts"`
C. `3.6 "volts"`
D. `4.8 "volts"`

Answer

A

Explanation

Energy of incident light `E = (12375)/(2000) = 6.18 eV`
`"According to relation" E = W_(0) + eV_(0)`
`rArr V_(0) = ((E_(0)- W_(0)))/(e ) = ((6.18 eV - 5.01 eV))/( e )`
`= 1.17 V ~~ 1.2 V`