A surface irradiated with light of wavelength 480 nm gives out electrons with maximum velocity v m / s, the cut off wavelength being 600 nm. The same surface would release electrons with maximum velocity 2 v m / s if it irradiated by light of wavelength

Question

A surface irradiated with light of wavelength 480 nm gives out electrons with maximum velocity v m / s, the cut off wavelength being 600 nm. The same surface would release electrons with maximum velocity 2 v m / s if it irradiated by light of wavelength (A) 300 nm (B) 360 nm (C) 384 nm (D) 400 nm

Tardigrade Admin · Accepted Answer

(1/2) mv 2=( hc /λ)-( hc /λ0) ... (i) (1/2) m (2 v )2=( hc /λ')-( hc /λ0) ... (ii) putting λ0=600 nm , λ=480 nm we get, λ'=300 nm

Q. A surface irradiated with light of wavelength $480 nm$ gives out electrons with maximum velocity $v m / s$ , the cut off wavelength being $600 nm$ . The same surface would release electrons with maximum velocity $2 v m / s$ if it irradiated by light of wavelength

300 nm

360 nm

384 nm

400 nm

$\frac{1}{2} m v^{2} = \frac{h c}{λ} - \frac{h c}{λ _{0}}$ ... (i)
$\frac{1}{2} m (2 v)^{2} = \frac{h c}{λ ^{'}} - \frac{h c}{λ _{0}}$ ... (ii)
putting $λ_{0} = 600 nm, λ = 480 nm$
we get, $λ^{'} = 300 nm$

Q. A surface irradiated with light of wavelength 480nm gives out electrons with maximum velocity vm/s, the cut off wavelength being 600nm. The same surface would release electrons with maximum velocity 2vm/s if it irradiated by light of wavelength