What is the velocity of a photon?

What is the relationship between the number of photons and the intensity of radiation?

If the energy of a photon is $E$ and its momentum is $p$,given by the relations $E = h\nu$ and $p = h/\lambda$,what is the velocity of the photon?

The number of photons per second on an average emitted by a source of monochromatic light of wavelength $600 \, nm$,when it delivers a power of $3.3 \times 10^{-3} \, W$,is: $(h = 6.6 \times 10^{-34} \, Js)$

If the energy of a photon is $10\,eV$,then its momentum is

$A$ laser produces a beam of light of frequency $5 \times 10^{14} \,Hz$ with an output power of $33 \,mW$. The average number of photons emitted by the laser per second is (Planck's constant $h = 6.6 \times 10^{-34} \,J \,s$)