The value of Planck's constant is
$6.63 \times 10^{-34}\; J / sec $
$6.63 \times 10^{-34}\; kg - m ^{2} / sec$
$6.63 \times 10^{-34} \;kg - m ^{2}$
$6.63 \times 10^{34} \;J-sec$
$(a)$ Estimate the speed with which electrons emitted from a heated emitter of an evacuated tube impinge on the collector maintained at a potential difference of $500\;V$ with respect to the emitter. Ignore the small inttial speeds of the electrons. The specific charge of the electron, $i.e.$, the $e / m$ is glven to be $1.76 \times 10^{11}\; C\; kg ^{-1}$
$(b)$ Use the same formula you employ in $(a)$ to obtain electron speed for an collector potential of $10 \;MV$. Do you see what is wrong? In what way is the formula to be modified?
The photo-electrons emitted from a surface of sodium metal are such that
A source $S_1$ is producing, $10^{15}$ photons per second of wavelength $5000 \;\mathring A.$ Another source $S_2$ is producing $1.02 \times 10^{15}$ photons per second of wavelength $5100\;\mathring A$. Then, $($ power of $S_2)/$ $($ power of $S_1)$ is equal to
According to photon theory of light which of the following physical quantities associated with a photon do not/does not change as it collides with an electron in vacuum
When wavelength of incident photon is decreased then