NEETPhysicsDual Nature of Matter
The variation of stopping potential ( V₀ ) with the frequency ( ) of incident light for a given photosensitive material is plotted as a straight line graph. If the slope of the graph is S and its intercept on the frequency axis is ₀ , which of the following gives the correct expressions for Planck's constant ( h ) and the work function ( ) of the material respectively? (Here e is the elementary charge)
Options
- AS e and S ₀ e
- BeS and eS ₀
- CeS and S ₀
- DS and eS ₀
Correct answer
B. eS and eS ₀
Step-by-step solution
According to Einstein's photoelectric equation: K_ = h - Since K_ = eV₀ , we can write: eV₀ = h - V₀ = ( h e ) - e Comparing this with the equation of a straight line y = mx + c , the slope m of the V₀ versus graph is: S = h e h = eS The intercept on the frequency axis (x-axis) is the threshold frequency ₀ , which occurs when V₀ = 0 : 0 = ( h e ) ₀ - e = h ₀ Substituting h = eS , we get: = eS ₀ Thus, Planck's constant is eS and the work function is eS ₀ . Answer: eS and eS ₀