This preview shows pages 1–4. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: 1. A circular coil lies flat on a horizontal table. A bar magnet is held above its center with its north pole pointing down. The magnet is fixed and does not move. It induces (when viewed from above) A) a clockwise current in the coil. B) a counterclockwise current in the coil. C) no current in the coil. D) a current whose direction cannot be determined from the information given. E) alternating current. Solution: Faradays law: t  = B . Magnet is stationary flax is not changing emf is zero no current in the coil. 2. A uniform magnetic field B is perpendicular to the area bounded by the U shaped conductor and a movable metal rod of length l. The rod is pushed along the U shaped conductor at a speed v . The total resistance of the loop is R . What is power needed to move the rod? A ) = 2 2 2 B l v P R B) R v Bl P 2 2 = C) R lv B P 2 2 = D) R v l B P 2 2 = E) R Blv P = Solution: P Find R v l B Given : , , , : R v l B R R Blv R I P R v l B Fv P R v l B lB R Blv IlB F R Blv R I Blv dis ext 2 2 2 2 2 2 2 2 2 2 = = = = = = = = = = = B v l B v l 3. The coil of a generator has 50 loops, each with a crosssectional area of 0.25 m 2 . What is the maximum emf generated by this generator if it is spinning with an angular velocity of 4.0 rad/s in a 2.0 T magnetic field? A) 20 V B) 40 V C) 60 V D) 80 V E) 100 V Solution: ( 29 ( 29 ( 29 V s rad m T NBA N N 100 / . 4 25 . . 2 50 2 max 1 max = = = = 4. The loop of wire is being moved to the right at constant velocity. A constant current I flows in the long straight wire in the direction shown. What statement is correct about the current induced in the loop? A) It is directed clockwise and is proportional to I B) It is directed counterclockwise and is proportional to I C) It is directed clockwise and is proportional to I 2 D) It is directed counterclockwise and is proportional to I 2 E) It is zero Solution: The direction of the induced current is clockwise and it is proportional to I. 5. The drawing shows the uniform magnetic field inside a long, straight solenoid. The field is directed into the plane of the drawing, and is increasing. What is the direction of the electric force on a positive point charge placed at point a ? A) To the left B) To the right C) Straight up D) Straight down E) The electric force at this point is zero Solution: To the left 6. An electric field can be produced by a A) changing magnetic field B) constant magnetic field C) either a constant or a changing magnetic field D) changing gravitational field E) none of the given answers Solution:  = A d B dt d l d E . An electric field can be produced by a changing magnetic field....
View Full
Document
 Fall '05
 Ogilvie
 Current

Click to edit the document details