If the eye receives an average intensity greater than 1.0 x 102 W/m2 , damage to the retina can occur. This quantity is called the damage threshold of the retina. (a) What is the largest average power (in mW) that a laser beam 1.5 mm in diameter can have and still be considered safe to view head-on? (b) What are the maximum values of the electric and magnetic fields for the beam in part (a)? (c) How much energy would the beam in part (a) deliver per second to the retina? (d) Express the damage threshold in W/cm2

If the eye receives an average intensity greater than 1.0 x 102 W/m2 , damage to the retina can occur. This quantity is called the damage threshold of the retina. (a) What is the largest average power (in mW) that a laser beam 1.5 mm in diameter can have and still be considered safe to view head-on? (b) What are the maximum values of the electric and magnetic fields for the beam in part (a)? (c) How much energy would the beam in part (a) deliver per second to the retina? (d) Express the damage threshold in W/cm2

Similar questions

Electromagnetic radiation from a 5.50 mW laser is concentrated on a 2.50 mm2 area. (a) What is the intensity in W/m2? W/m2 (b) Suppose a 6.00 nC static charge is in the beam. What is the maximum electric force (in N) it experiences? (Enter the magnitude.) N (c) If the static charge moves at 300 m/s, what maximum magnetic force (in N) can it feel? (Enter the magnitude.) N
At some instant and location, the electric field associated with an electromagnetic wave in vacuum has the strength 97.9 V/m. Find the magnetic field strength ?, the total energy density ?, and the power flow per unit area, all at the same instant and location. ?= T ?= J/m3 power flow per unit area: W/m2
An oscillating dipole antenna 1.71 m long with a maximum 37.0 mV potential creates a 500 Hz electromagnetic wave. (a) What is the maximum electric field strength created? V/m (b) What is the corresponding maximum magnetic field strength in the electromagnetic wave? (c) What is the wavelength of the electromagnetic wave? m
Suppose a source of electromagnetic waves radiates uniformly in all directions in empty space where there are no absorption or interference effects. (a) Show that the intensity is inversely proportional to r2, the distance from the source squared. (b) Show that the magnitudes of the electric and magnetic fields are inversely proportional to r.
The helium-neon lasers most commonly used in student physics laboratories have average power outputs of 0.250 mW. (a) If such a laser beam is projected onto a circular spot 2.36 mm in diameter, what is its intensity? W/m? (b) Find the peak electric field strength. V/m (c) Find the peak magnetic field strength.
Use phasor-form Maxwell’s equations to solve the following problems:
The ICNIRP also has guidelines for magnetic-field exposure for the general public. In the frequency range of 25 Hz to 3 kHz, this guideline states that the maximum allowed magnetic-field amplitude is 5>f T, where f is the frequency in kHz. Which is a more stringent limit on allowable electromagnetic-wave intensity in this frequency range: the electric-field guideline or the magnetic-field guideline? (a) The magnetic-field guideline, because at a given frequency the allowed magnetic field is smaller than the allowed electric field. (b) The electric-field guideline, because at a given frequency the allowed intensity calculated from the electric-field guideline is smaller. (c) It depends on the particular frequency chosen (both guidelines are frequency dependent). (d) Neither—for any given frequency, the guidelines represent the same electromagneticwave intensity
A 0.220–A current is charging a capacitor that has circular plates 10.1 cm in radius. The plate separation is 4.00 mm. (a) What is the time rate of increase of electric field between the plates? V/(m·s)(b) What is the magnetic field between the plates 5.00 cm from the center? T
Far enough from a source, the electric field and magnetic field are in spherical coordinates.is expressed as follows: E=(E0/r)sinusθsinus(wt-(w/c)r)θ̂ H = (√E0/ µ0 )(E0/r)sinusθsinus(wt-(w/c)r)∅̂ Find the total power emitted by this source.
Assume the helium-neon lasers commonly used in student physics laboratories have power outputs of 0.49 mW. (a) If such a laser beam is projected onto a circular spot 1.3 mm in diameter, what is its intensity? I= W m (b) Find the peak magnetic field strength. Bo= T (c) Find the peak electric field strength. E₁= V m
A certain 60.0 Hz AC power line radiates an electromagnetic wave having a maximum electric field strength of 45.2 kV/m. (a) What is the wavelength of this very low frequency electromagnetic wave? (b) What is its maximum magnetic field strength?