# Week 14 Hw 2

Topics: Magnetic field, Electromagnetism, Magnetic flux Pages: 4 (1164 words) Published: March 25, 2011
ELECTRICITY AND MAGNETISM Week 14: Homework 2 1. A spark can jump between two non – touching difference between them is sufficiently large. approximately 940 V is required to produce a spark How fast would a 1.3 m rod have to be moving in cause a spark to jump across the gap? [151 ms-1] conductors if the potential A potential difference of in an air gap of 1.0 × 10-4m. a magnetic field of 4.8 T to

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The wingspan (tip – to – tip) of a Boeing 747 jetliner is 59 m. The plane is flying horizontally at a speed of 220 ms-1. The vertical component of the Earth’s magnetic field is 5.0 × 10-6 T. Find the emf induced between the wing’s tips. [6.49 × 10-2 V] Near San Francisco, where the vertically downward component of the earth’s magnetic field is 4.8 × 10-5 T, a car is travelling forward at 25 ms-1. An emf of 2.4 × 10-3 V is induced between the sides of the car. a. Which side of the car is positive, driver’s side or the passenger’s side? [driver’s (American’s drive on the left hand side)] b. What is the width of the car? [2 m] A metal rod (length = 0.75 m) moves perpendicular to a magnetic field of 0.15 T. An emf of 0.24 V exists between the ends of the rod. How far does the rod move in 7.0 s? [14.9 m] The axle of a railway carriage is 1.5 m long and is moving with a velocity of 20 ms-1 north on a level track. The vertically upward component of the Earth’s magnetic flux density is 50 µT. a. Calculate (in mV) the emf induced between the ends of the axle. [15. mV] b. Does the east of the west end of the axle gain an excess of electrons? [west] When in the swept back position, the wings of the RAF F111C fighter – bomber have a span of 21 m. With the wings in this position while flying horizontally due magnetic north in a region where the Earth’s magnetic flux density id 50 µT and the angle of dip is – 60°, the F111C develops a potential difference of 0.77 V between its wing tips. At what speed is the plane flying? [847 ms-1]

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