Particle with Positive Charge - General Physics - Solved Past Paper, Exams of Physics

Download Particle with Positive Charge - General Physics - Solved Past Paper and more Exams Physics in PDF only on Docsity! 3. (25 pts) A particle with positive charge q and mass m is released from rest in a uniform electric field ~E directed along the positive x-axis. a) In what direction does the particle accelerate? By definition, electric fields point in the direction in which the electric force would be exerted on a positively charged particle. Since the field points to the right and the charged particle is positive, it would accelerate to the right. b) Assuming that the particle starts at x = 0 from rest, work out an expression for the position of the particle as a function of time. (Hint: First work out the acceleration and then use kinematics.) F = qE a = F m = qE m xf = xi + vit + 1 2 at2 = qEt2 2m c) How much work is done on the particle after moving a distance x through the electric field? W = ~F · ~ℓ W = qEx d) After moving a distance x, what is the speed of the particle? This could be done in one of two ways. It could be done with energy or with kinematics. Both give the same answer: ∆k = W 1 2 mv2 = qEx v2 = 2qEx m v = √ 2qEx m v2f = v 2 i + 2a(xf − xi) = 2qE m x v = √ 2qEx m All of your answers should be expressed in terms of the quantities given by the problem, q, m, and | ~E| = E.