lunes, 31 de marzo de 2008

Algunos ejercicios sencillos...

A positive particle (a proton) with charge 1.6.10-19C is moving with a velocity v=2.105 m/s in the positive z direction. A magnetic field B = 125.10-3 T (kilo teslas) is pointing in the positive y direction . Find the force acting on the particle.

A. 4 x 10-15 N, in the positive x-direction

B. 4 x 10-15 N, in the negative x-direction

C. 1.6 x 10-19 N, in the positive z-direction

D. 1.6 x 10-19 N, in the negative z-direction

E. zero



Two parallel wires carry currents of I1 = 20 - A and I2 = 10 -A, respectively, in the opposite direction and have length of 5 m each. The distance between wires is d = 1 cm. Find the force between the wires.

A. zero

B. 0.01 N, attraction

C. 0.01 N, repulsion

D. 0.02 N, attraction

E. 0.02 N, repulsion



Two circular coils of equal radius 2 cm are placed several centimeters apart. If viewed from left, the current in the closer loop is clockwise and decreasing with time at a constant rate. Describe the direction of the current in the furthest loop.

A. clockwise

B. counterclockwise

C. oscillating

D. zero

E. depends on the distance between coils


A particle with positive charge 3.10-6 -C is a distance 1,5.10-2 -m from a long straight wire that carries a current 5 -A. The particle is traveling with speed v = 1000 m/s perpendicular to the wire. What are the direction and magnitude of the force on the particle if it is moving away from the wire? (in N)

A) 1.0.10-8 up
B) 1.0.10-8 down

C) 2.0.10-8 up
D) 2.0.10-8 down
E) 2.0.10-7 up

Fuente:

NJIT Physics Department


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