hw7 solutions - homework 07 SMITH TAYLOR Due Mar 2 2008...

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homework 07 – SMITH, TAYLOR – Due: Mar 2 2008, 4:00 am 1 Question 1, chap 30, sect 1. part 1 of 1 10 points Suppose a new particle is discovered, and it is found that a beam of these particles passes undeflected through “crossed” electric and magnetic fields, where E = 302 V / m and B = 0 . 00288 T. If the electric field is turned off, the particles move in the magnetic field in circular paths of radius r = 1 . 33 cm. Determine q m for the particles from these data. 1 . 67262 × 10 27 kg = 9 . 57883 × 10 7 C / kg . Question 2, chap 29, sect 1. part 1 of 2 10 points = 1 . 75882 × 10 11 C / kg , and the proton charge-to-mass ratio is q p m p = 1 . 60218 × 10 19 C
homework 07 – SMITH, TAYLOR – Due: Mar 2 2008, 4:00 am 2 Explanation: Let : q = 1 . 60218 × 10 19 C , B x = 4 . 2 T , and B y = 1 . 8 T . Basic Concepts: Magnetic force on a mov- ing charge is given by vector F = qvectorv × vector B . Solution: vector B = (4 . 2 T) ˆ ı + (1 . 8 T) ˆ v = (370000 m / s) ˆ for the electron. Find: The vector expression for the force on the electron. This solves both part 1 and part 2. We will go through two methods of doing the problem. The first is more mathematically oriented and the second uses more of a reasoning argu- ment.
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