PHYSICS problems: wavelength questions?

1) Pulsed dye lasers emit light of wavelength 585nm in 0.450ms pulses to remove skin blemishes such as birthmarks. The beam is usually focused onto a circular spot 5.00mm in diameter. Suppose that the output of one such laser is 20.7W .
          a) What is the energy of each photon, in eV?
          b) How many photons per square millimeter are delivered to the blemish during each pulse?

2) To investigate the structure of extremely small objects, such as viruses, the wavelength of the probing wave should be about one-tenth the size of the object for sharp images. But as the wavelength gets shorter, the energy of a photon of light gets greater and could damage or destroy the object being studied. One alternative is to use electron matter waves instead of light. Viruses vary considerably in size, but 50.0nm  is not unusual. Suppose you want to study such a virus, using a wave of wavelength 5.00 nm .    If you use an electron of this wavelength, what would be its kinetic energy (in eV )?

3) A pulsed dye laser emits light of wavelength 585nm in 450us  pulses. Because this wavelength is strongly absorbed by the hemoglobin in the blood, the method is especially effective for removing various types of blemishes due to blood, such as port-wine-colored birthmarks. To get a reasonable estimate of the power required for such laser surgery, we can model the blood as having the same specific heat and heat of vaporization as water (4190 J/kgK , ). Suppose that each pulse must remove 2.00 ug of blood by evaporating it, starting at 33.0C.
       a) How much energy must each pulse deliver to the blemish? (in mJ)
       b) What must be the power output of this laser? (in W)
       c) How many photons does each pulse deliver to the blemish? (photons)

4) The human eye is most sensitive to green light of wavelength 505nm . Experiments have found that when people are kept in a dark room until their eyes adapt to the darkness, a single photon of green light will trigger receptor cells in the rods of the retina.
       a) To appreciate what a small amount of energy this is, calculate how fast a typical bacterium of mass 9.50×10−12g  would move if it had that much energy. (in mm/s)

5) What is the de Broglie wavelength of an electron accelerated from rest through a potential difference of 860.5 V? What is the de Broglie wavelength of a proton accelerated from rest through the same potential difference?
      a) What is the kinetic energy Kp of a proton when it is accelerated from rest through a potential difference of 860.5V ? (in J)