# 100points Magnet A has twice the magnetic field strength...

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dong (zd742) – HW23- Magnetism/EM – mcmeans – (00004) 1 This print-out should have 44 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. Tue, 2/22: Basics of Magnetism, 1-4 Wed, 2/23: RHR 1, 5-10 (omit 8) Thu, 2/24: RHR 2, 11-22 Fri, 2/25: F=BIl, 23-26 Mon, 2/28: Lenz’s Law, 27-36 Tue, 3/1: Motors, 37-44 Wed, 3/2: Test Review Fri, 3/4: Test: Electromagnetism and Quest 23 due at 8 am 001 10.0points Why will a magnet attract an ordinary nail or paper clip, but not a wooden pencil? 1. A nail or paper clip has molecular circuits which a wooden pencil does not have. 2. A magnet can generate electromagnetic waves which can be absorbed by a nail but not by a pencil. aluminum is magnetic. If it doesn’t stick, your friend might be wrong. 2. It cannot be checked without scraping the painted plastic. 3. Burn the refrigerator door and then an- alyze the remains with chemical reagents to find if aluminum is present. 4. Apply a small magnet to the door. If it sticks, your friend is wrong because aluminum is not magnetic. If it doesn’t stick, your friend might be right, (but not necessarily). correct
3. A nail or paper clip has a magnet inside which a wooden pencil does not have. 4. A nail or paper clip has magnetic do- mains which a wooden pencil does not have. 10.0points Magnet A has twice the magnetic field strength of magnet B (at equal distance) and at a certain distance pulls on magnet B with a force of 32 N. With how much force, then, does magnet B pull on magnet A? 002 10.0points 003 10.0points Magnet A has twice the magnetic field strength of magnet B (at equal distance) and at a certain distance pulls on magnet B with a force of 32 N. With how much force, then, does magnet B pull on magnet A?
A friend tells you that a refrigerator door, beneath its layer of white painted plastic, is made of aluminum. How could you check to see if this is true (without any scraping)? According to Newton’s Third law, both A and B are equally pulling on each other. If A pulls on B with 32 newtons, then B also pulls on A with 32 newtons. 004 10.0points A vertical electric wire in the wall of a building carries a DC current of 20 A upward. 1. Apply a small magnet to the door. If it sticks, your friend might be right because
dong (zd742) – HW23- Magnetism/EM – mcmeans – (00004) 2 I x S N E S N E (out)