Question

Find max ke of electron emitted by light of frequency 8× 10^14 for this metaal

Answer 1

K.E ( kinetic energy ) = h ( f - f₀ ) 

           h ----- > plank's constant

           f₀ ------> Threshold frequency

           f --------> Frequency 

------------------------------------------------

-------------------------------------------------------------------------

         h = 6.626 × 10⁻³⁴

         f₀ = 7× 10¹⁴ Hz

         f = 1 × 10¹⁵ Hz

K.E = (6.626 ×10⁻³⁴ ) ₓ [ (1 × 10¹⁵)  - (7× 10¹⁴)]

      = 1.987 × 10⁻¹⁹ J //