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Dual Nature Of Radiation And Matter

Question
CBSEENPH12040112

The photoelectric threshold wavelength of silver is 3250 × 10–10 m. The velocity of the electron ejected from a silver surface by ultraviolet light of wavelength 2536 × 10–10 m is

(Given h = 4.14 × 10–15 eVs and c = 3 × 108 ms–1)

  • ≈ 6 × 105 ms–1

  • ≈ 0.6 × 106 ms–1

  • ≈61 × 103 ms–1

  • ≈0.3 × 106 ms–1

Solution

A.

≈ 6 × 105 ms–1

straight lambda subscript 0 space equals space 3250 space straight x space 10 to the power of negative 10 end exponent space straight m
straight lambda space equals space 2536 space straight x space 10 to the power of negative 10 end exponent space straight m
straight ϕ space equals space fraction numerator 1242 space eV space minus nm over denominator 253.6 space nm end fraction space equals space 4.89 space eV
KE subscript max space equals space left parenthesis 4.89 space minus 3.82 right parenthesis space eV space equals space 1.077 space eV
1 half space mv squared space equals space 1.077 space straight x space 1.6 space straight x space 10 to the power of negative 19 end exponent
straight v space equals space square root of fraction numerator 2 space straight x space 1.077 space straight x space 1.6 space straight x space 10 to the power of negative 19 end exponent over denominator 9.1 space straight x space 10 to the power of negative 31 end exponent end fraction end root
straight v space equals space 0.6 space straight x space 10 to the power of 6 space straight m divided by straight s

Some More Questions From Dual Nature of Radiation and Matter Chapter

Wave property of electrons implies that they will show diffraction effects. Davisson and Germer demonstrated this by diffracting electrons from crystals. The law governing the diffraction from a crystal is obtained by requiring that electron waves reflected from the planes of atoms in a crystal interfere constructively (see in the figure).



If a strong diffraction peak is observed when electrons are incident at an angle ‘i’ from the normal to the crystal planes with distance’ between them (see figure), de Broglie wavelength λdB of electrons can be calculated by the relationship (n is an integer) 

Wave property of electrons implies that they will show diffraction effects. Davisson and Germer demonstrated this by diffracting electrons from crystals. The law governing the diffraction from a crystal is obtained by requiring that electron waves reflected from the planes of atoms in a crystal interfere constructively (see in the figure).



In an experiment, electrons are made to pass through a narrow slit of width’ comparable to their de Broglie wavelength. They are detected on a screen at a distance ‘D’ from the slit (see figure). 

Which of the following graph can be expected to represent the number of electrons ‘N’ detected as a function of the detector position ‘y’(y = 0 corresponds to the middle of the slit)? 

The time by a photoelectron to come out after the photon strikes is approximately

An alpha nucleus of energy 1 /2 mv2 bombards a heavy nuclear target of charge Ze. Then the distance of closest approach for the alpha nucleus will be proportional to 

If I0 is the intensity of the principal maximum in the single slit diffraction pattern, then what will be its intensity when the slit width is doubled?

The maximum number of possible interference maxima for slit-separation equal to twice the wavelength in Young’s double-slit experiment is