An ad agency has been hired to produce a commercial for a co…

An ad agency has been hired to produce a commercial for a company selling high-end musical instruments. The “plot” of the commercial involves a famous band playing the instruments on-stage, and while the client is pleased with the celebrity endorsement, they are worried that viewers will be too distracted by the band to recall the product itself after viewing the commercial. Which measurement technique might help determine which parts of the screen the audience is paying attention to, and whether they notice the instruments during the ad?

X and Y are two uncharged metal spheres on insulating stands…

X and Y are two uncharged metal spheres on insulating stands, and are in contact with each other. A positively charged rod R is brought close to X as shown in Figure (a). Sphere Y is now moved away from X, as in Figure (b). What are the final charge states of X and Y?

A resistor is made out of a long wire having a length L. Eac…

A resistor is made out of a long wire having a length L. Each end of the wire is attached to a terminal of a battery providing a constant voltage V0. A current I flows through the wire. If the wire were cut in half, making two wires of length L/2, and both wires were attached to the battery (the end of both wires attached to one terminal, and the other ends attached to the other terminal), what would be the total current flowing through the two wires?