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Dual Nature of Radiation and Matter One Mark Questions with Answer

12th Standard

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Physics

Time : 00:30:00 Hrs
Total Marks : 15
    15 x 1 = 15
  1. The wavelength λe of an electron and λp of a photon of same energy E are related by _____.

    (a)

    λp λe

    (b)

    \({ \lambda }_{ p }∝ \sqrt { { \lambda }_{ e } } \)

    (c)

    \({ \lambda }_{ p }∝ \frac { 1 }{ \sqrt { { \lambda }_{ e } } } \)

    (d)

    \({ \lambda }_{ p }∝ { \lambda }_{ e }^{ 2 }\)

  2. In an electron microscope, the electrons are accelerated by a voltage of 14 kV. If the voltage is changed to 224 kV, then the de Broglie wavelength associated with the electrons would _____.

    (a)

    increase by 2 times

    (b)

    decrease by 2 times

    (c)

    decrease by 4 times

    (d)

    increase by 4 times

  3. The wave associated with a moving particle of mass 3 x 10–6 g has the same wavelength as an electron moving with a velocity 6 x 106 ms-1. The velocity of the particle is _____.

    (a)

    1.82 x 10-18ms-1

    (b)

    9 x 10-2ms-1

    (c)

    3 x 10-31ms-1

    (d)

    1.82 x 10-15ms-1

  4. When a metallic surface is illuminated with radiation of wavelength λ, the stopping potential is V. If the same surface is illuminated with radiation of wavelength 2λ, the stopping potential is \(\frac{V}{4}\). The threshold wavelength for the metallic surface is _____.

    (a)

    (b)

    (c)

    \(\frac{5}{2}λ\)

    (d)

  5. If a light of wavelength 330 nm is incident on a metal with work function 3.55 eV, the electrons are emitted. Then the wavelength of the wave associated with the emitted electron is _____.(Take h = 6.6 x 10–34 Js)

    (a)

    < 2.75 ×10−9m

    (b)

    ≥ 2.75 × 10−9m

    (c)

    ≤ 2.75 × 10−12m

    (d)

    < 2.5 × 10−10m

  6. A photoelectric surface is illuminated successively by monochromatic light of wavelength λ and λ /2. If the maximum kinetic energy of the emitted photoelectrons in the second case is 3 times that in the first case, the work function of the material is _____.

    (a)

    \(\frac{hc}{\lambda}\)

    (b)

    \(\frac{2hc}{\lambda}\)

    (c)

    \(\frac{hc}{3\lambda}\)

    (d)

    \(\frac{hc}{2\lambda}\)

  7. In photoelectric emission, a radiation whose frequency is 4 times threshold frequency of a certain metal is incident on the metal. Then the maximum possible velocity of the emitted electron will be _____.

    (a)

    \(\sqrt { \frac { { hv }_{ o } }{ m } } \)

    (b)

    \(\sqrt { \frac { { 6hv }_{ o } }{ m } } \)

    (c)

    \(2\sqrt { \frac { { hv }_{ o } }{ m } } \)

    (d)

    \(\sqrt { \frac { { hv }_{ o } }{2m } } \)

  8. Two radiations with photon energies 0.9 eV and 3.3 eV respectively are falling on a metallic surface successively. If the work function of the metal is 0.6 eV, then the ratio of maximum speeds of emitted electrons in the two cases will be _____.

    (a)

    1:4

    (b)

    1:3

    (c)

    1:1

    (d)

    1:9

  9. A light source of wavelength 520 nm emits 1.04 x 1015 photons per second while the second source of 460 nm produces 1.38 x 1015 photons per second. Then the ratio of power of second source to that of first source is _____.

    (a)

    1.00

    (b)

    1.02

    (c)

    1.5

    (d)

    0.98

  10. If the mean wavelength of light from sun is taken as 550 nm and its mean power as 3.8 x 1026 W, then the number of photons emitted per second from the sun is of the order of _____.

    (a)

    1045

    (b)

    1042

    (c)

    1054

    (d)

    1051

  11. The threshold wavelength for a metal surface whose photoelectric work function is 3.313 eV is _____.

    (a)

    4125 \(\mathring { A } \)

    (b)

    3750\(\mathring { A } \)

    (c)

    6000\(\mathring { A } \)

    (d)

    2062.5\(\mathring { A } \)

  12. A light of wavelength 500 nm is incident on a sensitive metal plate of photoelectric work function 1.235 eV. The kinetic energy of the photoelectrons emitted is_____. (Take h = 6.6 x 10–34 Js)

    (a)

    0.58 eV

    (b)

    2.48 eV

    (c)

    1.24 eV

    (d)

    1.16 eV

  13. 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 _____.

    (a)

    \(\frac { hc }{ \lambda } -{ m }_{ e }+\frac { e^{ 2 }{ B }^{ 2 }{ R }^{ 2 } }{ { 2m }_{ e } } \)

    (b)

    \(\frac { hc }{ \lambda } +{ 2m }_{ e }{ \left[ \frac { eBR }{ { 2m }_{ e } } \right] }^{ 2 }\)

    (c)

    \(\\ \frac { hc }{ \lambda } -{ m }_{ e }{ c }^{ 2 }-\frac { e^{ 2 }{ B }^{ 2 }{ R }^{ 2 } }{ { 2m }_{ e } } \)

    (d)

    \(\frac { hc }{ \lambda } -{ 2m }_{ e }{ \left[ \frac { eBR }{ { 2m }_{ e } } \right] }^{ 2 }\)

  14. The work functions for metals A, B and C are 1.92 eV, 2.0 eV and 5.0 eV respectively. The metal/metals which will emit photoelectrons for a radiation of wavelength 4100 Å is/are _____.

    (a)

    A only

    (b)

    both A and B

    (c)

    all these metals

    (d)

    none

  15. Emission of electrons by the absorption of heat energy is called ______ emission.

    (a)

    photoelectric

    (b)

    field

    (c)

    thermionic

    (d)

    secondary

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