In a photocell circuit the stopping potential, `V_0`, is a measure of the maximum kinetic energy of the photoelectrons. The following graph shows experimentally measured values of stopping potential versus frequency v of incident light.

The values of Planks constant and the work function as determined from the graph are (taking the magnitude of electronic charge to be `e= 1.6 xx 10^(-19)C`)

Options

A. `6.4 xx 10^(-34) Js, 2.0 eV`
B. `6.0 xx 10^(-34) Js , 2.0 eV`
C. `6.4 xx 10^(-34) Js , 3.2 eV`
D. `6.0 xx 10^(-34) Js , 3.2 eV`

Answer

B

Explanation

`V=(hv)/(e ) - phi `
Hence for graph ` phi = 2 ev`
`(h)/ (e ) ` = slope =` (6)/(1.6 xx 10^(15))`
`h= (6xx 1.6 xx 10^(-19))/(1.6 xx 10^(15)) = 6.0 xx 10^(-34)`