A proton (mass ) is released from rest at point A inside a vacuum tube

PHYSICS · Multi-part · CBSE · Physics · Electrostatic Potential and Capacitance · Electrostatic Potential and Capacitance

Problem

A proton (mass mp=1.67×10−27 kgm_p = 1.67\times10^{-27}\,\text{kg}) is released from rest at point A inside a vacuum tube. Point A is at electric potential +250 V+250\,\text{V}, while point B, located 6.0 cm6.0\,\text{cm} away along the axis of the tube, is at electric potential +80 V+80\,\text{V}. Assume the proton experiences no forces other than the electrostatic interaction. (The elementary charge has magnitude e=1.60×10−19 Ce = 1.60 \times 10^{-19}\,\text{C}.) (a) Calculate the change in the proton–field system’s electric potential energy when the proton moves from A to B. (b) State whether the proton’s kinetic energy increases or decreases over this displacement and compute the numerical value of that change. (c) Determine the proton’s speed when it reaches point B.

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