Microwaves operate at a frequency of 2.40 GHz. Find the minimum thickness for a plastic tray with a refractive index of 1.45 that will cause enhanced reflection of microwaves incident normal to the tray.

Two forces produce equal torques on a door about the door hinge. the first force is applied at the midpoint of the door; the second force is applied at the doorknob. both forces are applied perpendicular to the door. which force has a greater magnitude?