A laser used to weld detached retains emits light with a wavelength $652$ nm in pulses that are of $20ms$ duration. The average power during each pulse is $0.6W$. The energy in each pulse and in a single photon are :

Q. A laser used to weld detached retinas emits light with a wavelength of $652nm$ in pulses that are $20.0ms$ in duration. The average power during each pulse is $0.6W$. Then

Q. A Laser light of wavelength $660nm$ is used to weld Retina detachment. If a Laser pulse of width $60ms$ and power $0.5kW$ is used, the approximate number of photons in the pulse are:
[Take Planck's constant $h=6.62\times {10}^{-34}Js$]

Q. A ruby laser produces radiations of wavelengths, 662.6 nm in pulse duration are 10${}^{-6}$s. If the laser produces 0.39 J of energy per pulse, how many photons are produced in each pulse?

Q. A pulsed laser emits rectangular pulses of width 1 nanosecond at a repetition rate of 1 kHz. If the average power output is 1 mW, the average power over a single pulse duration, in Watts, is

Q. Lifetimes of the molecules in the excited state are often measured by using pulsed radiation source of duration nearly in the nano second range. If the radiation source has the duration of 2 ns and the number of photons emitted during the pulse source is $2.5\times {10}^{15}$, calculate the energy of the source.