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Electrons are emitted with zero velocity...

Electrons are emitted with zero velocity from a metal surface when it is exposed to radiation of wavelength ` 6800` Å . Calculate threshold frequency `( v_0)` and work function `(W_0)` of the metal.

Text Solution

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Threshold wavelength `(lambfa_(0))=6800 Å=6800xx10^(-10) m`
As `c=v lambda :. v_(0)=c/lambda_(0)=(3.0xx10^(8)" ms"^(-1))/(6800xx10^(-10) m)=4.41xx10^(14) s^(-1)`
Work function `(W_(0))=hv_(0)=(6.626xx10^(-34) J s)(4.41xx10^(14) s^(-1))=2.92xx10^(-19) J`
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(a) Define Photoelectric effect ? Mention its one practical application in daily life. (b) Electrons are emitted with zero velocity from a mental surface when it is exposed to radiation of wavelength 6800 Å. Calculate thresholds freqency (V_o) and work function (W_o) of the mental.

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Knowledge Check

  • If a metal surface is exposed to electromagnetic radiation of frequency VgtV_0, then

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    B
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    C
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