Questions in Dual Nature of Radiation and Matter

Select	Question
	In a dark room of photography, generally red light is used. The reason is
	The work function of a metal is $1.6 \times {10^{ - 19}}$J. When the metal surface is illuminated by the light of wavelength 6400 Å, then the maximum kinetic energy of emitted photo-electrons will be (Planck's constant $h = 6.4 \times {10^{ - 34}}Js$)
	Ultraviolet radiations of $6.2\,eV$ falls on an aluminium surface (work function $4.2\;eV$). The kinetic energy in joules of the fastest electron emitted is approximately
	The work function for tungsten and sodium are 4.5 eV and 2.3 eV respectively. If the threshold wavelength $\lambda $ for sodium is $5460{\AA}$, the value of $\lambda $ for tungsten is
	A photon of energy 3.4 eV is incident on a metal having work function 2 eV. The maximum K.E. of photo-electrons is equal to
	The work function of a metallic surface is 5.01 eV. The photo-electrons are emitted when light of wavelength 2000Å falls on it. The potential difference applied to stop the fastest photo-electrons is $[h = 4.14 \times {10^{ - 15}}\;eV\sec ]$
	The photoelectric threshold wavelength for a metal surface is 6600 Å. The work function for this is
	Photoelectric effect was successfully explained first by
	The spectrum of radiation $1.0 \times {10^{14}}Hz$ is in the infrared region. The energy of one photon of this in joules will be
	A radio transmitter operates at a frequency of 880 kHz and a power of 10 kW. The number of photons emitted per second are