In optics, how do you get the refractive index

Acup of coffee sits on the dashboard of an automobile. the car goes around a sharp curve. even though you hold the cup still, coffee still splashes out. this can best be explained due to a) density. b) friction. c) gravity. d) inertia.

Two conductors, a and b, are each in the shape of a tetrahedron. but of different sizes. they are charged in the following manner: 1. tetrahedron a is charged from an electrostatic generator to charge q. 2. tetrahedron a is briefly touched to tetrahedron b. 3. steps 1 and 2 are repeated until the charge on tetrahedron b reaches a maximum value. if the charge on tetrahedron b was q/4 after the first time it touched tetrahedron a. what is the final charge qbmax on tetrahedron b?

See the attachment and solve question 5th