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Enhanced EOC: Problem 24.23 MC A proton moves with a speed of 4.5x10 m/s in the

ID: 1445049 • Letter: E

Question

Enhanced EOC: Problem 24.23 MC A proton moves with a speed of 4.5x10 m/s in the directions shown in the figure. A 0.55 T magnetic field points in the positive x-direction.(Figure 1) You may want to revie (DA ages 777-783 For help with math skills, you may want to review: Vector Components Figure 1 V of 1 Part C If the particle is an electron, what is the direction of the magnetic force in figure (a)? z direction Submit Hints My Answers Give Up Review Part Correct Part D What is the magnitude of the magnetic force in figure (b)? Express your answer using three significant figures. F 3.96x10 2 N Hints My rs Give Up Review Part Subm Correct Part E What is the direction of the magnetic force in figure (b)? zy direction (45 degrees between the -z and -y axes Submit Hints My Answers Give Up Review Part Incorrect, Try Again Part F If the particle is an electron, what is the direction of the magnetic force in figure (b)? Please Choose

Explanation / Answer

a) Magnetic force on moving charge,

Fm = q ( v X B)    {cross prodcut}

q = - 1.6 x 10^-19 C

v = - 4.5 x 10^7 j m/s

B = 0.55 T i


Fm = -1.6 x 10^-19 ( -4.5x10^7j X 0.55 i)

cross product of -j x i = - (-k) = k

Fm = -1.6 x 10^-19 (0.55 x 4.5 x 10^7 k )

Fm = 3.96 x 10^-12 (-k) N


direction - > -k = along -ve z direction

D) magnitude = 3.96 x 10^-12 N

E) v = 4.5 x 10^7 ( -cos45 j + sin45 k)

for proton. q = +v

F = 1.6 x 10^-19 [ (-3.18E+7 j + 3.18E+7k) x (0.55 i) ]

F = (1.6 x 10^19) [ (1.75 x 10^7 k ) + (1.75 x 10^7 j ) ]

F = 2.8 x 10^-12 j + 2.8 x 10^-12 k N


direction:

= 45 degrees between +ve y and + z axes )

magnitude = sqrt(2.8^2 + 2.8^2) x 10^-12 =3.96 x 10^-12 N


F) for electron,

q = - 1.6 x 10^-19 C

everything else is same.

so direction will be 45 deg between -y and -z axes.

magnitude = 3.96 x 10^-12 N