Q29.The surface of certain metal is first illuminated with light of wavelength π1 = 350 nm and then, by a light of wavelength π2 = 540 nm . It is found that the maximum speed of the photoelectrons in the two cases differ by a factor of 2. The work function of the metal (in eV) is close to 1240 (Energy of photon = eV ) πin nm (1) 2.5 (2) 1.8 (3) 5.6 (4) 1.4
What This Question Tests
This question requires applying Einstein's photoelectric equation for two different wavelengths to determine the work function of the metal, using the given relation between maximum photoelectron speeds.
Concepts Tested
Formulas Used
E = hc/Ξ»
KE_max = E - Ξ¦
KE_max = 1/2 mv_maxΒ²
π NCERT Sections This Tests
11.2 β The Work Function Of Caesium Metal Is 2.14 Ev. When Light Of
Physics Class 12 Β· Chapter 11
11.2 The work function of caesium metal is 2.14 eV. When light of frequency 6 Γ1014Hz is incident on the metal surface, photoemission of electrons occurs. What is the (a) maximum kinetic energy of the emitted electrons, (b) Stopping potential, and (c) maximum speed of the emitted photoelectrons?
11.7 β The Work Function For A Certain Metal Is 4.2 Ev. Will This Metal Give
Physics Class 12 Β· Chapter 11
11.7 The work function for a certain metal is 4.2 eV. Will this metal give hotoelectric emission for incident radiation of wavelength 330 nm?
11.8 β Light Of Frequency 7.21 Γ 1014 Hz Is Incident On A Metal Surface.
Physics Class 12 Β· Chapter 11
11.8 Light of frequency 7.21 Γ 1014 Hz is incident on a metal surface. Electrons with a maximum speed of 6.0 Γ 105 m/s are ejected from the surface. What is the threshold frequency for photoemission of electrons?
π Question Details
- Chapter
- Dual Nature of Matter
- Topic
- Photoelectric Effect
- Year
- 2019
- Shift
- 09 Jan Shift 1
- Q Number
- Q29
- Type
- MCQ
- NCERT Ref
- Class 12 Physics Ch 11: Dual Nature of Radiation and Matter
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