Two radiations of photons energies 1 eV and 2.5 eV, successively illuminate a photosensitive metallic surface of work function 0.5 eV. The ratio of the maximum speeds of the emitted electrons is

Question

Two radiations of photons energies 1 eV and 2.5 eV, successively illuminate a photosensitive metallic surface of work function 0.5 eV. The ratio of the maximum speeds of the emitted electrons is (A) 1: 4 (B) 1: 2 (C) 1: 1 (D) 1: 5

Tardigrade Admin · Accepted Answer

According to Einsten's photoelectric effect, the K.E. of the radiated electrons K ⋅ E max =E-W (1/2) m v12=(1-0.5) e V=0.5 eV (1/2) m v22=(2.5-0.5) eV =2 eV (v1/v2)=√(0.5/2)=(1/√4)=(1/2)

Q. Two radiations of photons energies $1 e V$ and $2.5 e V$ , successively illuminate a photosensitive metallic surface of work function $0.5 e V$ . The ratio of the maximum speeds of the emitted electrons is

$1 : 4$

$1 : 2$

$1 : 1$

$1 : 5$

According to Einsten's photoelectric effect, the K.E. of the radiated electrons
$K \cdot E_{m a x} = E - W$
$\frac{1}{2} m v_{1}^{2} = (1 - 0.5) e V = 0.5 e V$
$\frac{1}{2} m v_{2}^{2} = (2.5 - 0.5) e V = 2 e V$
$\frac{v _{1}}{v _{2}} = \frac{0.5}{2} = \frac{1}{4} = \frac{1}{2}$

Q. Two radiations of photons energies 1eV and 2.5eV, successively illuminate a photosensitive metallic surface of work function 0.5eV. The ratio of the maximum speeds of the emitted electrons is

1:4

1:2

1:1

1:5