How is a critical angle related to total internal reflection(TIR)? What are the 2 conditions for TIR to occur? List 2 uses of TIR.

The density of a substance is 4.0 g/cm3. if a sample of the substance has a volume of 25 cm3 then what is the mass

The chemical effect of the endocrine system is longer lasting than the chemical effect of the nervous system. select the best answer from the choices provided t f

The rigid beam is supported by the three suspender bars. bars ab and ef are made of aluminum and bar cd is made of steel. if each bar has a cross-sectional area of 450 mm2, determine the maximum value of p if the allowable stress is (σallow)st = 200 mpa for the steel and ( σallow)al = 150 mpa for the aluminum. est = 200 gpa and eal = 70 gpa.