Dual nature of matter and radiation

What is photoelectric effect?

Rest mass of photons

0

Speed of photons in air or vacuum

3×10⁸ m/s

Charge of photons

neutral

Energy of photon

E= hc /λ= hf

where h=6.626×10^-34 m² kg / s

λ= wavelength

f=frequency

Momentum of photon

P=h/λ

where h=6.626×10^-34 m² kg / s

λ= wavelength

Relation between initial and final Potential and kinetic energy of a photon

P.E(initial)=P.E(final)

K.E(initial)=K.E(final)

Relation of luminous intensity with no. of photons and K.Emax

Increase in luminous intensity increase no. of photons

K.E max remains unchanged

What is work function (ϕ)? what does it depend upon?

Minimum amount of energy required to eject an electron from a metal surface

What is Einstein’s photoelectric equation?

K.E(max)= E-ϕ

=hf-ϕ

=hc/λ -ϕ

where h=6.626×10^-34 m² kg / s

λ= wavelength

E=Energy

ϕ= Work function

What is threshold frequency (f₀)?

Minimum frequency of incident radiation which may cause photoelectric effect

f₀=ϕ/h

ϕ=hf₀

where,

h=6.626×10^-34 m² kg / s

ϕ= Work function

Relation between K.Emax and Threshold frequency

What is Threshold wavelength (λ)?

Maximum wavelength of incident radiation which may cause photoelectric effect

λ₀=hc/ϕ

ϕ=hc/λ₀

where,

h=6.626×10^-34 m² kg / s

ϕ= Work function

Relation between threshold wavelength and K.E max

Stopping potential formula

Relation between stopping potential (V₀)and K.Emax

V₀=K.E(max)/e

where, e=1.6×10⁻¹⁹C