Presentation is loading. Please wait.

Presentation is loading. Please wait.

April 7 AP Physics. AP Practice Exam April 28 ACT day 1 pm Not optional.

Similar presentations


Presentation on theme: "April 7 AP Physics. AP Practice Exam April 28 ACT day 1 pm Not optional."— Presentation transcript:

1 April 7 AP Physics

2 AP Practice Exam April 28 ACT day 1 pm Not optional

3 In: Two 1 kg spheres each carry a charge of magnitude 1C. How does F E, the strength of the electric force between the spheres, compare to F G, the strength of their gravitational attraction? a)F E < F G b)F E =F G c)F E >F G d)If the charges on the spheres are of the same sign, then F E >F G ; but if the charges on the spheres are of the opposite sign, then F E { "@context": "http://schema.org", "@type": "ImageObject", "contentUrl": "http://images.slideplayer.com/2/771121/slides/slide_3.jpg", "name": "In: Two 1 kg spheres each carry a charge of magnitude 1C.", "description": "How does F E, the strength of the electric force between the spheres, compare to F G, the strength of their gravitational attraction. a)F E < F G b)F E =F G c)F E >F G d)If the charges on the spheres are of the same sign, then F E >F G ; but if the charges on the spheres are of the opposite sign, then F E

4 Objective: To learn about static electricity: –Millikan Oil Drop Experiment –Electric potential energy –Electric potential –Capacitance –Parallel plate capacitors

5 Homework Check 18, 20, 24, 30

6 Robert Millikan Oil Drop experiment Measured charge to mass ratio of electron Published in 1913 Nobel prize 1932

7 Millikan oil-drop experiment qE = mg q/m=g/E q e = -1.6x10 -19

8

9

10 Electrical potential energy Work

11 Electric potential energy The work done to bring a charge from infinity to a particular distance = - potential energy the charge has at that point. U E =-Work Also, the change in PE from one point to another = -work done to change the position. ΔU E =-W

12 In a field generated by a point charge: U E =kq 1 q 2 r In a uniform field: ΔU E =qEΔd

13 Both Gravitational potential and Electrical potential energy depend on position

14 Electric potential The energy per each individual charge. Measured in Volts V = U E q

15

16 Electric potential: uniform field V = -Ed

17 Electric potential: Point charge V = kq r

18 Equipotential lines

19 Equipotential surfaces

20

21 No work is done moving around on an equipotential surface. Work is done moving from one equipotential surface to another.

22 Capacitance A capacitor is a device that stores energy in the form of charges. C = Q ΔV

23 Parallel Plate capacitor Stores energy by building up opposite charges on each plate. C = Є o A d

24 Energy stored in a capacitor U c = ½ QV= ½ CV 2

25 Equivalent Capacitance parallel circuits

26 C=Q/V V 1 =V 2 =V e Q 1 +Q 2 =Q e so…C 1 +C 2 =C e

27 Equivalent Capacitance Series circuits

28 C=Q/V V 1 +V 2 =V e Q 1 =Q 2 =Qe so…1/C 1 +1/C 2 =1/C e

29

30

31

32 Out: What is the equivalent capacitance of the circuit between a and b ?


Download ppt "April 7 AP Physics. AP Practice Exam April 28 ACT day 1 pm Not optional."

Similar presentations


Ads by Google