Giving 40 points!

i need to design an experiment to support the hypothesis that light travels in straight lines except at the point it enters a new medium.

a) what can i use for this experiment?
b) how do i use it to complete this experiment? how can i conduct an experiment using it?

Which type of electromagnetic waves are dangerous enough to be used to kill cancerous cells? (a)gamma rays (b)visible light (c)infrared light (d)microwaves

If a refrigerator is a heat pump that follows the first law of thermodynamics, how much heat was removed from food inside of the refrigerator if it released 380j of energy to the room?

Steam is generated in a boiler of a cogeneration plant at 10 mpa and 450°c at a steady rate of 5 kg/s. in normal operation, steam expands in a turbine to a pressure of 0.5 mpa and is then routed to the process heater, where it supplies the process heat. steam leaves the process heater as a saturated liquid and is pumped to the boiler pressure. in this mode, no steam passes through a condenser, which operates at 20 kpa. (a) determine the power produced in the turbine and the rate at which process heat is supplied in this mode. (b) determine the power produced in the turbine and the rate of process heat supplied if only 60 percent of the steam is routed to the process heater and the remainder is expanded to the condenser pressure. (3.32 mw; 9.69 mw; 4.25 mw; 5.82 mw)