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Dual Nature Of Radiation And Matter

Question
CBSEENPH12047732
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The work functions for metals A, B and C are respectively 1.92 eV, 2.0 eV and 5 eV. According to Einstein's equation, the metals which will emit photoelectrons for a radiation length 4100 Ao is /are 

  • none

  • A only

  • A and B only

  • all the three metals

Solution

C.

A and B only

That metal will emit photoelectrons which has work function lower than that obtained with the radiation of 4100 Ao.

Work function for the wavelength of 4100 Ao is

W = h cλ    =6.62 × 10-14 × 3 ×1084100 × 10-10    = 4.8 × 10-19 J     = 4.8 × 10-191.6 × 10-19 eVW  = 3 eV

Now we have 

WA = 1.92 eV

WB = 2.0 eV

WC = 5 eV

since WA < W  and  WB < W,  hence A and B will emit photoelectrons.

Some More Questions From Dual Nature of Radiation and Matter Chapter

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