UNIT VIII: Dual Nature of Radiation and Matter - Online Test
Q1. The threshold wavelength for a metal surface whose photoelectric work function is 3.313 eV is
Answer : Option B
Explaination / Solution:
Q2. A light of wavelength 500 nm is incident on a sensitive plate of photoelectric work function
1.235 eV. The kinetic energy of the photo electrons emitted is be (Take h = 6.6
× 10–34 Js)
Answer : Option C
Explaination / Solution:
Q3. Photons of wavelength λ are incident on a metal. The most energetic electrons ejected from the metal are bent into a circular arc of radius R by a perpendicular magnetic field having magnitude B. The work function of the metal is
Answer : Option D
Explaination / Solution:
Centripetal
force (Fc.p) = Magnetic force (FB)
Q4. The work functions for metals A, B and C are 1.92 eV, 2.0 eV and 5.0 eV respectively. The metals which will emit photoelectrons for a radiation of wavelength 4100 Å is/are
Answer : Option B
Explaination / Solution:
Both (A) and (B) emits the electrons, because
its work function is less than 3.02eV.
Q5. Emission of electrons by the absorption of heat energy is called………emission.
Answer : Option C
Explaination / Solution:
No Explaination.
