Define efficiency. Give an example. ...

[elizabeth18]

Define efficiency. Give an example.

Question 2

A large, metallic, spherical shell has no net charge. It is supported on an insulating stand and has a small hole at the top. A small tack with charge Q is lowered on a silk thread through the hole into the interior of the shell. The tack is now allowed to touch the interior surface of the shell. After this contact, what is the charge on the tack?
  1.Q
  2.Q/2
  3.0
  4.-Q/2
  5.-Q

[carolinefletcherr]

Answer to Question 1

Efficiency is the ratio of the work output to the work input. Example: The work input
to a machine is 50 N m  and the work output is 40 N m  . The efficiency is 40 50 , or
80 percent.

Answer to Question 2

3