Lights of wavelengths λ 1=340 nm and λ 2=540 nm are incident on a metallic surface. If the ratio of the maximum speeds of the electrons ejected is 2 , the work function of the metal is

Question

Lights of wavelengths λ 1=340 nm and λ 2=540 nm are incident on a metallic surface. If the ratio of the maximum speeds of the electrons ejected is 2 , the work function of the metal is (A) 2 eV (B) 1.85 eV (C) 1 eV (D) 1.5 eV

Tardigrade Admin · Accepted Answer

λ 1=350nm,λ 2=540nm,(V1/V2)=2⇒ V1=2V and V2=V ( hc /λ1)=φ+(1/2) m (2 V )2 (hc/λ 2)=φ+(1/2)mV2 (hc/λ 1)-(hc/λ 2)× 4=φ-4φ hc(.(4/540 nm)-(1/340 nm).)=3φ φ=1.8eV

Q. Lights of wavelengths $λ_{1} = 340 nm$ and $λ_{2} = 540 nm$ are incident on a metallic surface. If the ratio of the maximum speeds of the electrons ejected is $2$ , the work function of the metal is

$2 e V$

$1.85 e V$

$1 e V$

$1.5 e V$

Q. Lights of wavelengths λ1​=340nm and λ2​=540nm are incident on a metallic surface. If the ratio of the maximum speeds of the electrons ejected is 2 , the work function of the metal is

2eV

1.85eV

1eV

1.5eV

λ1​=350nm,λ2​=540nm,V2​V1​​=2⇒V1​=2VandV2​=V λ1​hc​=ϕ+21​m(2V)2 λ2​hc​=ϕ+21​mV2 λ1​hc​−λ2​hc​×4=ϕ−4ϕ hc(540nm4​−340nm1​)=3ϕ ϕ=1.8eV

Q. Lights of wavelengths $λ_{1} = 340 nm$ and $λ_{2} = 540 nm$ are incident on a metallic surface. If the ratio of the maximum speeds of the electrons ejected is $2$ , the work function of the metal is

$2 e V$

$1.85 e V$

$1 e V$

$1.5 e V$