If suitable light is allowed to fall on ...

If suitable light is allowed to fall on a clean metal surface, electrons are emitted from the surface. This phenomenon is called the photo - electric effect. Usually a radiation in the UV region and also in some cases in the visible region produces such an effect. The velocity and K.E. of the emitted electrons are measured by electric field . If wavelength of 470 nm falls on the surface of potassium metals, electrons are emitted with a velocity of `6.4 xx 10^(4) m sec^(-1)`
Stopping potential of given circuit is ,

`1.86 xx 10^(-21) J`

`18.6 xx 10^(-25) J`

`1.86 xx 10^(-23) J`

`1.86 xx 10^(-20)`

Verified by Experts

The correct Answer is:

ATOMIC STRUCTURE
FIITJEE|Exercise COMPREHENSION -XI|3 Videos
ATOMIC STRUCTURE
FIITJEE|Exercise MATCHING LIST TYPE QUESTIONS|5 Videos
ATOMIC STRUCTURE
FIITJEE|Exercise COMPREHENSION -IX|3 Videos
ALKYL AND ARYL HALIDES
FIITJEE|Exercise NUMERICAL BASED QUESTIONS|1 Videos
CARBOHYDRATES, AMINO ACIDS, POLYMERS AND PRACTICAL ORGANIC CHEMISTRY
FIITJEE|Exercise EXERCISE|4 Videos

If suitable light is allowed to fall on a clean metal surface, electrons are emitted from the surface. This phenomenon is called the photo - electric effect. Usually a radiation in the UV region and also in some cases in the visible region produces such an effect. The velocity and K.E. of the emitted electrons are measured by electric field . If wavelength of 470 nm falls on the surface of potassium metals, electrons are emitted with a velocity of 6.4 xx 10^(4) m sec^(-1) The work function of potassium metal is :

`4.2 xx 10^(-19) J`

`1.86 xx 10^(-21) J`

`4.25 xx 10^(-30)J`

`4.2 xx 10^(-18)J`

`1.86 xx 10^(-21) J`

`4.24 xx 10^(-19) J`

`1.98 xx 10^(-22)J`

`4.25 xx 10^(-22)J`

Of speeds from `0` to a certain maximum

Of same de Broglie wavelength

Of same kinetic energy

Of same frequency