$1 \ J$ is equal to how many electron volt?

If $E$ and $P$ are the energy and the momentum of a photon respectively,then on reducing the wavelength of the photon:

The number of photons emitted per second by a bulb of $66 \ W$ power emitting waves of wavelength $600 \ nm$ is . . . . . . . $(h = 6.6 \times 10^{-34} \ J \cdot s)$

$A$ photon,an electron,and a uranium nucleus all have the same wavelength. The one with the most energy is:

An atom absorbs a photon of wavelength $500\,nm$ and emits another photon of wavelength $600\,nm$. The net energy absorbed by the atom in this process is $n \times 10^{-4}\,eV$. The value of $n$ is ............ [Assume the atom to be stationary during the absorption and emission process] (Take $h = 6.6 \times 10^{-34}\,Js$ and $c = 3 \times 10^8\,m/s$)

$A$ photodiode sensor is used to measure the output of a $300 W$ lamp kept $10 m$ away. The sensor has an opening of $2 cm$ in diameter. How many photons enter the sensor if the wavelength of the light is $660 nm$ and the exposure time is $100 ms$? (Assume that all the energy of the lamp is given off as light and $h = 6.6 \times 10^{-34} J s$)