21.The central spot of newton ring is __ due to transmitted light:?
dark
bright
may be both

22.A path difference 3λ /4 is equal to the phase change of:?
pi rad
pi/2 rad
3pi/4 rad
3pi/2 rad

23. When the movable mirror of a Michelson interferometer is moved at a distance of 0.5 mm, 2000 fringes are observed. The wavelength of light used is?
    5000A
    500mm
    5000mm
    none

24.In Michelson interferometer if the moveable mirror is displaced through a distance equal to lamda/2. The path difference between two waves produced is:?
lamda/2
2lamda
lamda
none

25. The least distance which can be measured with Michelson interferometer is?
    lamda/2
    lamda
    2lamda
    none
26. Light of wavelength 500 nm is incident on a diffraction grating on which 1000 lines / cm have been ruled. Find the maximum number of order of spectra:?
    30
    40
    50
    none

27.Colour of white light having maximum speed is:?
red
blue
violet
green

28. If the separation between two planes of atoms in a crystal be d / 2, the Bragg’s equation would be?
    2dSin@=n lamda
    dSin@=n lamda
    d/2Sin@=n lamda

29.Light is most refined form of?
energy
wave
matter
all of these

30. Which one of the following can be polarized?
    gamma rays
    x rays
    radiowaves
    micro waves
    none of these
    all of these
31. Spitting of spectral line in the presence of external electric field is called?
    Zemaan effect
    Stark effect
    Pauli exclusion princlple
    None
32. Splitting of sharp spectral line in the presence of weak magnetic field is?
    Stark effect
    Zemaan effect
    Stern Gerlach experiment
33. Sommerfeld model gives an idea about?
    Z component of angular momentum
    Presence of subshells
    Azimuthal quantum numbers
    About elliptical shape of orbitals
    b,c & d
34. No two electrons can have same set of 3 Quantum numbers?
    True
    False
35. Zemaan effect due to interaction b/w magnetic field and orbital as well as spin magnetic moment is called?
    Normal zemaan effect
    Anamalous zemaan effect
    Linear stark effect
    Quadratic stark effect
36. The electric dipole moment governed due to external electric field is accompanied with?
    Linear Stark effect
    Quadratic stark effect
37. Which experiment confirms spin up and spin down of single electron atom?
    Frank Hertz Experiment
    Stern Gerlach experiment
    Cavendish experiment
38. The existence of excited states in Mercury vapours was confirmed by?
    Stern Gerlach Experiment
    Frank Hertz Experiment
39. In stern Gerlach experiment the deflecting force due to magnetic energy is maximum when magnetic field is?
    When magnetic moment is parallel to magnetic field
    When magnetic moment is antiparallel to magnetic field
    When magnetic moment is perpendicular to magnetic field
    None of these
40. The selection rules for allowed transitions ∆ml=??
    +-1
    0,+-1
    None