Gr Xii Physics- Part-2 Revision 2

15 Questions | Total Attempts: 70

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Gr Xii Physics- Part-2 Revision 2

Mixed Questions from Ray Optics, Wave Optics , Dual Nature


Questions and Answers
  • 1. 
    What is path difference for destructive interference?
    • A. 

      (a) nλ

    • B. 

      (b) n(λ +1)

    • C. 

      (c) (2n + 1)λ/2

    • D. 

      (d) (n +1)λ/ 2

  • 2. 
    When exposed to sunlight, thin films of oil on water of ten exhibit brilliant colours due to the phenomenon of
    • A. 

      Interference

    • B. 

      Diffraction

    • C. 

      Dispersion

    • D. 

      Refraction

  • 3. 
    What happens, if the monochromatic light used in Young’s double slit experiment is replaced by white light?
    • A. 

      (a) No fringes are observed.

    • B. 

      (b) All bright fringes become while.

    • C. 

      (c) All bright fringes have colour between violet and red.

    • D. 

      (d) Only the central fringe is white and all other fringes are coloured.

  • 4. 
    The phenomenon of interference is based on
    • A. 

      (a) conservation of momentum.

    • B. 

      (b) conservation of energy.

    • C. 

      (c) conservation of momentum and energy.

    • D. 

      (d) quantum nature of light.

  • 5. 
    A double slit interference experiment is carried out in air and the entire arrangement is dipped in water. The fringe width
    • A. 

      (a) increases

    • B. 

      (b) decreases

    • C. 

      (c) remains unchanged.

    • D. 

      (d) fringe pattern disappears.

  • 6. 
    A double convex lens of refractive index µ1 is immersed in a liquid of refractive index µ2. The lens will act as transparent plane sheet when
    • A. 

      (a) µ1 = µ2

    • B. 

      (b) µ1 > µ2

    • C. 

      (c) µ1 < µ2

    • D. 

      (d) µ1 = 1/ μ2

  • 7. 
    When a ray of light enters from one medium to another, then which of the following does not change?
    • A. 

      Frequency

    • B. 

      Wavelength

    • C. 

      Speed

    • D. 

      Amplitude

  • 8. 
    Mirage is a phenomenon due to
    • A. 

      Refraction of light

    • B. 

      Reflection of light

    • C. 

      Total internal reflection of light

    • D. 

      Diffraction of light

  • 9. 
    A convex lens is dipped in a liquid whose refractive index is equal to the refractive index of the lens. Then its focal length will
    • A. 

      Become zero

    • B. 

      Become infinite

    • C. 

      Become small, but non-zero

    • D. 

      Remain unchanged

  • 10. 
    Two beams of red and violet color are made to pass separately through a prism (angle of the prism is 60°). In the position of minimum deviation, the angle of refraction will be
    • A. 

      (a) 30° for both the colors

    • B. 

      (b) greater for the violet color

    • C. 

      (c) greater for the red color

    • D. 

      (d) equal but not 30° for both the colors

  • 11. 
    In photoelectric effect, the maximum velocity of the emitted electron depends on
    • A. 

      (a) Intensity of the incident light

    • B. 

      (b) Frequency of the incident light

    • C. 

      (c) threshold frequency

    • D. 

      (d) Both (b) and (c) above

  • 12. 
    Two metals A and B have work function 2eV and 4 eV respectively .which metal has a lower threshold wavelength for the photoelectric effect?
    • A. 

      (a) A

    • B. 

      (b) B

    • C. 

      (c) same for both

    • D. 

      (d) cannot say

  • 13. 
    An electron and proton have the same De Broglie wavelength . Which one of these has the higher kinetic energy?. Which one is moving faster?
    • A. 

      Electron has higher K.E and it will move faster

    • B. 

      Proton has higher K.E and it will move faster

    • C. 

      Both will have same kinetic energy, but proton will move faster.

    • D. 

      Both will have same kinetic energy, but electron will move faster.

  • 14. 
    Which one do you like?
    • A. 

      (a) a -> p, b -> q , c -> r.

    • B. 

      (b) a -> r, b -> q , c -> p.

    • C. 

      (c) a -> r, b -> p , c -> q.

    • D. 

      (d) a -> p, b -> r , c -> q.

  • 15. 
    The de Broglie wavelength of an electron accelerated to a potential of 400 V is approximately
    • A. 

      (a) 0.03 nm

    • B. 

      (b) 0.04 nm

    • C. 

      (c) 0.12 nm

    • D. 

      (d) 0.06 nm

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