Exam2_2005Fall

Exam2_2005Fall - Physics 8.02 Exam Two Mashup Fall 2005...

This preview shows pages 1–4. Sign up to view the full content.

Physics 8.02 Exam Two Mashup Fall 2005 Some (possibly useful) Relations: inside closedsurface o Q d κ ε ⋅= ∫∫ EA G G w points from inside to outside d A G moving from to b ab b a a VV V ∆= = Es G G d 0 d −⋅= G G v many point charges 1 4 N i i oi q V πε = = rr GG V Q C = C Q V = parallelplate o A C d = U = 1 2 C V 2 = Q 2 2C series 1 2 11 CC =+ 1 C parallel 1 2 C where is the resistivity ρρ = EJ V = i R L R A ρ = 1 R parallel = 1 R 1 + 1 R 2 R series = R 1 + R 2 2 2 ohmic heating V Pi V i R R =∆ = = 2 ˆ 4 o q c r µ π × = << vr Bv G G G 2 ˆ r 4 o I d d × = B sr G G ˆ points source observer rf r o mt o through contour o dI Bs G G v where I through is the current flowing through any open surface bounded by the contour: through open surface I d = JA G G d s right-handed with respect to d A sgl loop d d N dt dt Φ = Ed s BdA v ext q Fv B G G G ext d Fs B G 2 cent. Fm v = r = perpendicular to loop, right-handed with respect to IA I μn n G ± ± = × τ μB G G G z zz dB F dz = Cross-products of unit vectors: ˆˆ ˆˆˆˆ 0 ×=×= × = ii jjkk ˆˆ ˆ × = ijk ˆ × = j ki ˆ × = ki j Some potentially useful numbers 2 97 2 0 1 N m T m 91 0 4 1 0 4C eo k µπ == × = × A Breakdown of air E ~ 3 x 10 6 V/m Earth’s B Field B ~ 5 x 10 -5 T = 0.5 Gauss Speed of light c = 3 x 10 8 m/s Electron charge e = 1.6 x 10 -19 C Avogadro’s number N A = 6.02 x 10 23 mol -1

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

View Full Document
MIT PHYSICS DEPARTMENT 8.02 Exam Two Mashup Fall 2005 FAMILY (last) NAME GIVEN (first) NAME Student ID Number Your Section: ___L01 MW 10 am ____L02 MW 1 pm Your Group (e.g. 10A): ______________ Problem Score Grader 1 (21 points) 2 (4 points) 3 (25 points) 4 (25 points) 5 (25 points) TOTAL 8.02 Exam #2 Mashup Fall 2005
MIT PHYSICS DEPARTMENT p. 1 of 11 Problem 1: Seven Short Questions. Circle your choice for the correct answer. Question A (3 points out of 21 points): A B Both of the above pictures show an iron filings representation of the magnetic fields generated by a loop of current held above a permanent magnet. In both pictures the coil has a current which is counterclockwise when viewed from above. The magnet, however, has been flipped over between A & B. What is true about the direction of the magnet and the force it exerts on the coil? 1) In A its North pole is up and it attracts the coil. 2) In B its North pole is up and it attracts the coil. 3) In A its North pole is up and it repels the coil. 4) In B its North pole is up and it repels the coil. Question B (3 points out of 21 points): You are given two long straight pieces of wire and a semicircle of wire and asked to construct a shape that, when a current is passed through it, creates a large B field at the center of the semi-circle (that is, the center of the circle from which the semi-circle is cut).

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.

{[ snackBarMessage ]}

Page1 / 12

Exam2_2005Fall - Physics 8.02 Exam Two Mashup Fall 2005...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online