What happens to a light ray passing through the center of a lens? for plato

When does your body conduct current more readily?

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?

Give one example to show that when substances are mixed,it may result in a chemical or a physical change depending on the conditions.