Red, blue, green and violet colour lights are one by one made incident on a photocathode. It is observed that only one colour light produces photo-electrons. That light is

Question

Red, blue, green and violet colour lights are one by one made incident on a photocathode. It is observed that only one colour light produces photo-electrons. That light is (A) Red (B) Blue (C) Green (D) Violet

Tardigrade Admin · Accepted Answer

Order of wavelength of given coloured lights are

λ_{v} < λ_{b} < λ_{g} < λ_{r}

Similarly, frequency order of these coloured lights are

f_{v} > f_{b} > f_{g} > f_{r}

Thus, energy order of these lights are

E_{v} > E_{b} > E_{g} > E_{r}

Therefore, violet light can produce photo electrons.

Q. Red, blue, green and violet colour lights are one by one made incident on a photocathode. It is observed that only one colour light produces photo-electrons. That light is

Red

Blue

Green

Violet

Order of wavelength of given coloured lights are λv​<λb​<λg​<λr​ Similarly, frequency order of these coloured lights are fv​>fb​>fg​>fr​ Thus, energy order of these lights are Ev​>Eb​>Eg​>Er​ Therefore, violet light can produce photo electrons.

Order of wavelength of given coloured lights are
$λ_{v} < λ_{b} < λ_{g} < λ_{r}$
Similarly, frequency order of these coloured lights are
$f_{v} > f_{b} > f_{g} > f_{r}$
Thus, energy order of these lights are
$E_{v} > E_{b} > E_{g} > E_{r}$
Therefore, violet light can produce photo electrons.