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السلام عليكم
أحبتي منتدى الكهربية
لدي بعض الأسئلة في الكربية الله يخليكم
ساعدوني في حلها
. An electron has a velocity of 6.0  106 m/s in the positive x direction at a point where the magnetic field has the components Bx = 3.0 T, By = 1.5 T and Bz = 2.0 T. What is the magnitude of the acceleration of the electron at this point?

a. 2.1  1018 m/s2 b. 1.6  1018 m/s2 c. 2.6  1018 m/s2
d. 3.2  1018 m/s2 e. 3.7  1018 m/s2


33. One long wire carries a current of 30 A along the entire x axis. A second long wire carries a current of 40 A perpendicular to the xy plane and passes through the point (0, 4, 0) m. What is the magnitude of the resulting magnetic field at the point y = 2.0 m on the y axis?

a. 4.0 µT b. 5.0 µT c. 3.0 µT d. 7.0 µT e. 1.0 µT

34. A coil is wrapped with 300 turns of wire on the perimeter of a circular frame (radius = 8.0 cm). Each turn has the same area, equal to that of the frame. A uniform magnetic field is turned on perpendicular to the plane of the coil. This field changes at a constant rate from 20 to 80 mT in a time of 20 ms. What is the magnitude of the induced emf in the coil at the instant the magnetic field has a magnitude of 50 mT?

a. 24 V b. 18 V c. 15 V d. 10 V e. 30 V



35. A current may be induced in a coil by
a. Moving one end of a bar magnet through the coil.
b. Moving the coil toward one end of the bar magnet.
c. Holding the coil near a second coil while the electric current in the second coil is increasing.
d. All of the above.
e. None of the above.
36. What is the inductance of a series RL circuit in which R = 1.0 K if the current increases to one-third of its final value in 30 µs?
a. 74 mH b. 99 mH c. 49 mH d. 62 mH e. None of the above