When a flat slab of transparent material is placed under water, the critical angle for light traveling from the slab into water
is found to be 60°. What will the critical angle be if the slab is surrounded by air? Take the index of refraction for water to be 1.33. d) 45.6 c) 44.2 e) 47.3 a) 40.6 b) 42.5
Monoammonium phosphate effectively smothers the fire, while sodium bicarbonate induces a chemical reaction which extinguishes the fire. Fire extinguishers with a Class C rating are suitable for fires in “live” electrical equipment.