1. (a) What is the intensity in W/m² of a laser beam used to burn away cancerous tissue that, when 90.0% absorbed, puts 650 J of energy into a circular spot 1.9 mm in diameter in 4 s? Hint: The laser is a collimated beam of light and does not produce a spherical wave. W/m² (b) Reflect on how this intensity compares to the average intensity of sunlight (about 1W/m²) and the implications that would have if the laser beam entered your eye. Note how your answer depends on the time duration of the exposure. The intensity of a laser is about be very damaging if they enter your eye. ✓times that of the sun, so clearly lasers can

Assume the intensity of solar radiation incident on the cloud tops of the Earth is 1 677 W/m². (a) Taking the average Earth-Sun separation to be 1.496 x 10¹1 m, calculate the total power radiated by the Sun. 4.905E26 x Your response is within 10% of the correct value. This may be due to roundoff error, or you could have a mistake in your calculation. Carry out all intermediate results to at least four-digit accuracy to minimize roundoff error. W (b) Determine the maximum value of the electric field in the sunlight at the Earth's location. kv/m (c) Determine the maximum value of the magnetic field in the sunlight at the Earth's location. μT

The figure below depicts spectral reflectance measurements for three different materials:  a green leaf from a healthy plant, a sheet of shiny blue paper, and the palm of a human hand.  The measurements are labeled 1 (black line), 2 (red line), and 3 (blue line).  Match the measurements to the most appropriate material type

B4. A bone sample has a density p = 1.2x10³ kg/m³, a molar mass m = 217 g/mol and an interaction cross section per atom o = 6.0x10-22 cm². Determine the linear attenuation coefficient µ (in cm-¹) and the half value layer (in cm). Assume there is no scattering when the radiation interacts with the bone sample. Express the values to 3 significant figures, if necessary.