One day on a spacecraft corresponds to $2$ days on the earth. The speed of the spacecraft relative to the earth is
$1.5 \times {10^8}m{s^{ - 1}}$
$2.1 \times {10^8}m{s^{ - 1}}$
$2.6 \times {10^8}m{s^{ - 1}}$
$5.2 \times {10^8}m{s^{ - 1}}$
A photon, an electron and a uranium nucleus all have the same wavelength. The one with the most energy
The work function of aluminium is $4.2eV.$ If two photons, each of energy $3.5 eV$strike an electron of aluminium, then emission of electrons will be
The curve drawn between velocity and frequency of photon in vacuum will be a
Which of the following is true for photon
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