Following results are observed when sodium metal is irradiated with different wavelengths. Calculate (a) Threshold wavelength and (b) Planck's constant. 1 (nm) 500 450 400
`v xx 10^-5 (cm s_1)` 2.55 4.35 5.35

The photoelectric threshold wavelength of a metal is 230 nm. Determine the maximum kinetic energy in joule and eV of the ejected electron from metal surface when it is exposed to a radiation of wavelength 180 nm. (Planck's constant h = 6.63 xx 10^-34 J-S, C = 3 xx 10^8 m//sec .)

Calculate the de Broglie wavelength of proton, if it is moving with a speed of 2 xx 10^5 m//s .

The work function of metals is in the range of 2 eV to 5 eV. Find which of the following wavelength of light cannot be used for photoelectric effect. (Consider, Planck's constant = 4 xx 10^(-15) eV.s , velocity of light = 3 xx 10^(8) m//s )

The threshold wavelength for silver is 3800overset@ A . Calculate maximum kinetic energy in eV of photoelectrons emitted when ultraviolet light of wavelength 2600overset@ A falls on it. Also calculate stopping potential ( 1 eV = 1.6 xx 10^-19 J , Planck's constant = h = 6.63 xx 10^-34 Js , speed of light in vacuum = 3 xx 10^8 m//s ).

A photon of wavelength 4 xx 10^-7 m strikes on metal surface, the work function of the metal being 2.15eV. Calculate The velocity of the Photoelectron. (1ev = 1.6020 xx 10^-19 J)

Calculate the de Broglie wavelength of proton, if its speed is 10^7 cm//s . Given: mass of proton = 1.67 xx 10^-27 kg .

Calculate the energy radiated in 30 seconds by perfectly black sphere of radius5cm maintained at 127^@C . (Stefan's constant s = 5.7 xx 10^-8 J//m^2sk^4)

An electron of work function 1.4 eV is emitted with a velocity 5 xx 10^6 m/s .The wavelength of the incident radiation is

A black body is at a temperature of 5760 K. The energy of radiation emitted by the body at wavelength 250 nm is U_(1) , at wavelength 500 nm is U_(2) and at 1000 nm is U_(3) , Wien's constant, b=2.88xx10^(6) nm K, which of the following is correct ?