An electron (charge = -1.6 x 10^-19C) is moving at 3 x 10^5 m/s in the positive x direction. A magnetic field of 0.8 T is in the positive z-direction. The magnetic force on the electron is:
Correct answer: D. 4 x 10^-14N in the negative y direction
- A. 0
- B. 4 x 10^-14N in the negative z direction
- C. 4 x 10^-14N in the positive z direction
- D. 4 x 10^-14N in the negative y direction
Explanation
Magnetic force is given byF = BqVF = 0.8 x 1.6x10-19 x 3x105F = 3.84x10-14 round it of to 4x10-14 NUse Fleming's left-hand rule to determine direction.
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About Electromagnetic Induction
Changing magnetic flux induces an emf according to Faraday's law, while Lenz's law gives the direction that opposes the change producing it. Transformers apply induction between coils to step alternating voltage up or down, with turns ratio, current transformation and energy losses determining practical operation.
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