Each plate of an air-filled parallel-plate air capacitor has an ...

[gbarreiro]

Each plate of an air-filled parallel-plate air capacitor has an area of 0.0040 m2, and the separation of the plates is 0.080 mm. An electric field of 5.3  106 V/m is present between the plates.
 
  What is the energy density between the plates? (0 = 8.85  10-12 C2/N  m2)
  A) 124 J/m3 B) 170 J/m3 C) 84 J/m3 D) 250 J/m3
   E) 210 J/m3

Question 2

A factory siren indicating the end of a shift has a frequency of 90.0 Hz. The speed of sound is 343 m/s.
 
  (a) What frequency is perceived by the occupant of a car traveling towards the factory at 25.0 m/s?
  (b) What frequency is perceived by the occupant of a car traveling away from the factory at 30.0 m/s?

[zogaridan]

Answer to Question 1

A

Answer to Question 2

(a) 96.6 Hz (b) 82.1 Hz

[gbarreiro]

Thanks for the timely response, appreciate it

[cassie_ragen]

Excellent