What will it be the critical angle if light is incident from glass n=1.5 in to the air n=1​

Boiling water is an example of physical change. true or false

What explosion in the upper solar atmosphere releases about as much energy as millions of 100-megaton hydrogen bombs exploding simultaneously?

Asquare isothermal chip is of width w=5 mm on a side and is mounted in a substrate such that its side and back surfaces are well insulated; the front surface is exposed to the flow of a coolant at tinf=15 °c. from reliability considerations, the chip temperature must not exceed t=85 °c. if the coolant is air and the corresponding convection coefficient is h=200 w/m2 x k, what is the maximum allowable "power" of the chip? if the coolant is a liquid for which h=3000 w/m2 x k, what is the maximum allowable power of the chip?