One observation that suggests that the Earth has a dense central ...

[jasdeep_brar]

One observation that suggests that the Earth has a dense central core is that
 
  A) the Earth has plate tectonics
  B) surface rocks have the same density as the overall density of the planet
  C) surface rocks have a lower density than overall density of the planet
  D) surface rocks have a higher density than the overall density of the planet

Question 2

The current through a 50.  resistor is I = 0.80 sin (240. t) amperes.
 
  (a) At what frequency does the current vary?
  (b) How much power is dissipated in the resistor?

[Perkypinki]

Answer to Question 1

C

Answer to Question 2

(a) 38. Hz
(b) 16. W

[jasdeep_brar]

Thanks for the timely response, appreciate it

[ebonylittles]

Great answer, keep it coming