Question

Problem 3. A charged ball of mass 2.00 grams is suspended by a light thread. A uniform electric field of magnitude 6.00 x 10 N/C making an angle 45.0° with the horizontal is present in the region. The charge is at rest with the thread making an angle 30.0 with the vertical. (a) Is the charge positive or negative? Justify your answer b) Determine the magnitude of the charge and the tension in the cord.

Answer 1

Concept :- here we use force on a charge in an electric field and Newton's law of motion to find the answer, ***************************************************************************************************
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Concept: - here we use force on a charge in an electric field and Newton's law of motion to find the answer, a) Since the charge is deflected along the direction of field, it must be positive b) E_x = (6 times 10^5 N/c)cos phi = 4.24 times 10^5 N/c E_y = (6 times 10^5 N/c)sin phi = 4.24 times 10^5 N/c from equilibrium of charge T cos theta + q E_y = mg or, T cos theta = mg - q E_y equation (1) and T sin theta = q E_x equation (II) from (1) and (II) tan theta = q E_x/mg - q E_y, theta = 45 degrees m = 2 times 10^-3 kg so, q = 2.31 times 10^-8 c - charge and T = q E_x/sin theta = 1.386 times 10^-2 N