HW 7 solution

# HW 7 solution - song(shs546 – Homework 7 – weathers...

This preview shows pages 1–2. Sign up to view the full content.

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

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: song (shs546) – Homework 7 – weathers – (22202) 1 This print-out should have 14 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 10.0 points Two conductors insulated from each other are charged by transferring electrons from one conductor to the other. After 1 . 386 × 10 14 have been transferred, the potential difference between the conductors is 16 . 1 V. The charge on an electron is- 1 . 60218 × 10 − 19 C . What is the capacitance of the system? Correct answer: 1 . 37926 × 10 − 6 F. Explanation: Let : e =- 1 . 60218 × 10 − 19 C , N = 1 . 386 × 10 14 electrons , and V = 16 . 1 V . One conductor gains a charge of Q =- N e while the other gains a charge of- Q. The capacitance of the system is C = q V =- N e V =- (1 . 386 × 10 14 ) (- 1 . 60218 × 10 − 19 C) 16 . 1 V = 1 . 37926 × 10 − 6 F . 002 10.0 points A spherical capacitor consists of a conducting ball of radius 9 cm that is centered inside a grounded conducting spherical shell of inner radius 12 cm. What charge is required to achieve a potential of 1023 V on the ball of ra- dius 9 cm? The Coulomb constant is 8 . 98755 × 10 9 N · m 2 / C 2 . Correct answer: 4 . 09767 × 10 − 8 C. Explanation: Let : k e = 8 . 98755 × 10 9 N · m 2 / C 2 , a = 9 cm = 0 . 09 m , b = 12 cm = 0 . 12 m and V = 1023 V . The capacitance of a spherical capacitor is given by C = a b k e ( b- a ) . The charge required to achieve a potential difference V between the shell and the ball is given by Q = C V = 1 k e a b V ( b- a ) = 1 (8 . 98755 × 10 9 N · m 2 / C 2 ) × (0 . 09 m) (0 . 12 m) (1023 V) (0 . 12 m)- (0 . 09 m) = 4 . 09767 × 10 − 8 C . keywords: 003 (part 1 of 2) 10.0 points A 59 m length of coaxial cable has a solid cylindrical wire inner conductor with a di- ameter of 3 . 081 mm and carries a charge of 8 . 49 μ C. The surrounding conductor is a cylindrical shell and has an inner diameter of 9 . 228 mm and a charge of- 8 . 49 μ C. Assume the region between the conductors is air. The Coulomb constant is 8 . 98755 × 10 9 N · m 2 / C 2 . What is the capacitance of this cable? Correct answer: 2 . 99212 nF. Explanation: Let : k e = 8 . 98755 × 10 9 N · m 2 / C 2 , Q = 8 . 49 μ C , ℓ = 59 m , a = 3 . 081 mm , and b = 9 . 228 mm ....
View Full Document

{[ snackBarMessage ]}

### Page1 / 6

HW 7 solution - song(shs546 – Homework 7 – weathers...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online