Photoelectric work function for a surface is 2.4 eV. Light of wavelength `6.8 xx 10^(-7)`m shines on the surface. Find the frequency of incident light and also the threshold frequency. Will there be photoelectric emission or not ?
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The work function for a metal is `40 eV`. To emit photo electrons of zero velocity from the surface of the metal the wavelength of incident light shou
Correct Answer - 31 `W_(0)+K=hv` `4xx1.6xx10^(-19)=(6.62xx10^(-34)xx3xx10^(8))/(lambda)` `lambda=3.18xx10^(-7)=31xx10^(-8) m` `lambda=31 nm`
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Photoelectric emission is observed from a surface for frequencies `v_(1)` and `v_(2)` of incident radiation `(v_(1)gtv_(2))` If max K.E of photoelectr
Correct Answer - B `hv_(1)=hv_(0)+KE_(1)" "......(1)` `hv_(2)=hv_(0)+KE_(2)" "......(2)` `(KE_(1))/(KE_(2))=(1)/(K)=(hv_(1)-hv_(0))/(hv_(2)-hv_(0))` `k(hv_(1)-hv_(0))=hv_(2)-hv_(0)` `khv_(1)-khv_(0)=hv_(2)-hv_(0)` `kv_(1)-kv_(0)=v_(2)-v_(0)` `kv_(1)-v_(2)=(k-1)v_(0)` `v_(0)=(kv_(1)-v_(2))/((k-1))`
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The work function of Cs is 2.14eV.Find (a) threshold frequency for Cs (b) Wavelength of incident light if the photo current is brought to zero by stop
Wave function `omega = 2.14eV` (a) Threshold frequency `omega = hnu_(0)` `nu_(0) = (omega)/(h) = (2.14 xx 1.6 xx 10^(-19))/(6.62 xx 10^(-34))` `=5.174 xx 10^(14)H_(2)` (b) `"As "k_(max) = eV_(0)=...
2 Answers 3 views
A parallel beam of monochromatic light of frequency v is incident on a surface. Intensity of the beam is I and area of the surface is A. Find the forc
Correct Answer - (i) `(IA)/(c)` , (ii) `(2IA)/(c)` (iii) `(Iacostheta)/(c)` , (iv) `(2IAcos^(2)theta)/(c)`
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Find the number of photons emitted per second by a 25 W source of monochromatic light of wavelength `6600 Å`. What is the photoelectric current assumi
Correct Answer - `8.33 xx 10^(19), 0.4 A`
2 Answers 3 views
Calculate the kinetic energy of a photoelectron (in eV) emitted on shining light of wavelength `6.2 xx 10^(-6)m` on a metal surface. The work function
Correct Answer - 0.1 eV
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If the speed of photoelectrons is `10^(4) ms^(-1)`, what should be the frequency of incident radiation on the potassium metal ? Work function of potas
Correct Answer - `5.56 xx 10^(14) Hz`
2 Answers 2 views
The photoelectric threshold wavelength for lithium is `8000 Å`. Find the maximum kinetic energy in eV of the emitted electrons from the surface by lig
Correct Answer - 0.5156 eV
2 Answers 1 views
When light of wavelength 400nm is incident on the cathode of photocell, the stopping potential recorded is 6V. If the wavelength of the incident light
Correct Answer - 4.97 V
2 Answers 7 views
(a) If the wavelength of the light incident on a photoelectric cell be reduced from `lambda_(1)` to `lambda_(2) Å`, then what will be the change in th
Correct Answer - 2.3 eV, `1.44 xx 10^(-6)` Vm
2 Answers 1 views