{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Physics 106 Homework3

Physics 106 Homework3 - Physics 106 Homework#3 Submitting...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Physics 106 Homework #3 Submitting Answers Remember to be careful about units. Implicit multiplication is not understood. Type 3*x, not 3x Defined Constants The following constants can be used by name throughout this assignment: ke = 8.99×10 9 Nm 2 /C 2 qe = 1.6×10 –19 C mp = 1.67×10 –27 kg me = 9.11×10 –31 kg eps0 = 8.85×10 –12 C 2 /(Nm 2 ) g = 9.80 m/s 2 . Problem 3.1 Purpose: Find the capacitance of an unusual parallel-plate capacitor. Problem with data for try #1 : Consider the Earth and a cloud layer 818 m above the planet to be the plates of a parallel- plate capacitor. If the cloud layer has an area of 1.00 km 2 =1.00×10 6 m 2 , what is the capacitance? Additional input values d (m): 860, 852 Defined symbols: d distance of cloud layer over the earth in m A area of cloud layer in m 2 The answer is C , the capacitance in F Hints: Make use of the equation for the capacitance of a parallel-plate capacitor. It's a rough approximation, but it gives us an idea of the capacitance of the system. The formula is C=ε 0 A/d Range of answers: 9.40×10 –9 F to 1.30×10 –8 F . Problem 3.2 Purpose: Capacitors can only hold so much charge. When the voltage exceeds the breakdown voltage, the capacitor discharges. Be sure you learn the relationship between voltage and electric field here. Problem with data for try #1 : Consider the Earth and a cloud layer 818 m above the planet to be the plates of a parallel-
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
plate capacitor. If an electric field strength greater than 3.00×10 6 V/m causes the air to break down and conduct charge (lightning), what is the maximum charge the cloud can hold? Additional input values d (m): 860, 852 Defined symbols: d distance of cloud layer over the earth in m E electric field strength in V/m The answer is Q , the charge in C Hints: Make use of the fundamental relationship for capacitors: Q=CV . You're not given the voltage, so you have to find it from the electric field. In practice, we usually write the units of electric field as V/m rather than N/C, though they're the same thing. (From now on I'll write V/m almost always!) If you remember this, you can use the units to help you remember the relation between electric field and voltage in capacitors: E=V/d Range of answers: 20.0 C to 30.0 C . Problem 3.3 Purpose: This is a good exercise in keeping track of qualitative relationships with capacitors. You'll see problems like this on quizzes and tests. They're simple to work if you have the right ideas, but if you're a bit hazy, they can be confusing.
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern