Wavelengths belonging to Balmer series lying in the range of 450 nm to 750 nm were used to eject photoelectrons from a metal surface whose work function is 2.0 eV . Find (in eV ) the maximum kinetic energy of the emitted photoelectrons. (Take hc=1242 eV nm .)

Question

Wavelengths belonging to Balmer series lying in the range of 450 nm to 750 nm were used to eject photoelectrons from a metal surface whose work function is 2.0 eV . Find (in eV ) the maximum kinetic energy of the emitted photoelectrons. (Take hc=1242 eV nm .) (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

Wavelengths corresponding to minimum wavelength (λ_min ) or maximum energy will emit photoeiectrons having kinetic energy which is maximum. (λmin ) belonging to Balmer series and Lying in the given range (450 nm to 750 nm) corresponds to transition from (n = 4 to n = 2). Here,

(E)_{4} = - \frac{13 \cdot 6}{( 4 ) ^{2}} = - 0 \cdot 85 eV

(and E)_{2} = - \frac{13 \cdot 6}{( 2 ) ^{2}} = - 3 \cdot 4 eV

∴ Δ E = E_{4} - E_{2} = 2 \cdot 55 eV

K_{max} = Energy of photon - work function = 2 \cdot 55 - 2 \cdot 0 = 0 \cdot 55 eV

Q. Wavelengths belonging to Balmer series lying in the range of 450nm to 750nm were used to eject photoelectrons from a metal surface whose work function is 2.0eV . Find (in eV ) the maximum kinetic energy of the emitted photoelectrons. (Take hc=1242eVnm .)

Q. Wavelengths belonging to Balmer series lying in the range of $450 nm$ to $750 nm$ were used to eject photoelectrons from a metal surface whose work function is $2.0 e V$ . Find (in $e V$ ) the maximum kinetic energy of the emitted photoelectrons. (Take $h c = 1242 e V nm$ .)