KCET 2024 Physics Solved Paper

ϕ=2.4‌eV,λ= ?
ϕ=‌

hc

λ

λ0=‌

hc

ϕ

=‌

6.626×10−34×3×108

2.4×1.6×10−19

‌λ0=‌

19.8×10−26

3.84×10−19

=5.156×10−26+19 =5.156×10−2
‌λ0=515‌nm
The threshold wavelength for the photo emission is 515 nm .
Therefore, for the wavelength greater than the threshold wavelength the photo emission is not possible.