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WorksheetsDual nature
Total questions: 10
Worksheet time: 7mins
Light of frequency 1.9 times the threshold frequency is incident on a photosensitive material. If the frequency is halved and intensity is doubled, the photocurrent becomes
quadrupled
doubled
halved
zero
Threshold wavelength for a metal having work function W0 is X. What is the threshold wavelength for the metal having work function 2W0?
4λ
2λ
λ/2
λ/4
Radiations of frequency v are incident on a photosensitive metal. The maximum K.E. of the photoelectrons is E. When the frequency of the incident radiation is doubled, what is the maximum kinetic energy of the photoelectrons?
2E
4E
E + hv
E – hv
Maximum kinetic energy (Ek) of a photoelectron varies with frequency (v) of the incident radiation as
The stopping potential V0 for photoelectric emission from a metal surface is plotted along y-axis and frequency v of incident light along x-axis. A straight line is obtained as shown. Planck’s constant is given by
slope of the line
product of the slope of the line and charge on electron
intercept along y-axis divided by charge on the electron
product of the intercept along x-axis and mass of the electron
The energy of photon of wavelength 450 nm is
2.5 × 10-17 J
1.25 × 10-17 J
4.4 × 10-19 J
2.5 × 10-19 J
The kinetic energy of an electron is 5 eV. Calculate the de broglie wavelength associated with it. (h = 6.6 × 10-34 Js, me = 9.1 × 10-31 kg)
5.47 Å
10.9 Å
2.7 Å
None of these
Work function of three metals A, B and C are 4.5 eV, 4.3 eV and 3.5 eV respectively. If a light of wavelength 4000 Å is incident on the metals then
photoelectrons are emitted from A.
photoelectrons are emitted from B.
photoelectrons are emitted from C.
photoelectrons are emitted from all the metals.
If K.E. of free electron is doubled, its de Broglie wavelength will change by factor
1/√8
√2
1/2
2
A proton, a neutron, an electron and an a-particle have same energy. Then their de Broglie wavelengths compare as
λp = λn > λe > λα
λα < λp = λn < λe
λe < λp = λn > λα
λe = λp = λn = λα
