InterviewSolution
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InterviewSolution
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Figure shown three points. `X, Y` and `Z` forming an equilaternal triangle of side `s` in an unifrom electric field of strength `E`. A unit positive test charge is moved from `X` to `Y`, from `Y` to `Z`, and from `Z` back to `X`. Which one of the following correctly gives the work done against electrical forces in moving the charge along the various parts o fthis path ?A. `{:("X to Y"," Y to Z"," Z to X",),(+Es,+"Es "cos 60^(@).,-"Es "cos 60^(@).,):}`B. `{:("X to Y"," Y to Z"," Z to X",),(0,-"Es "cos 60^(@).,+"Es "cos 60^(@).,):}`C. `{:("X to Y"," Y to Z"," Z to X",),(+Es,+"Es "cos 60^(@).,-"Es "cos 60^(@).,):}`D. `{:("X to Y"," Y to Z"," Z to X",),(0,-"Es "sin 60^(@).,+"Es "sin 60^(@).,):}` |
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Answer» Correct Answer - D From `E = (dV)/(dx)`, work done in moving a unit positive test charge in an unifrom electric field of strength `E` is given by work done `V = int dV = - int Edx` `= - E int dx = - Ed` where `d` is the distancetravelled parallel to the direction of `E`. From `X` to `Y, d = 0`. Therefore work done `= 0` From `Y` to `Z, d = +s sin 60^(@)` Therefore work done is `Es sin 60^(@)` From `Z` to `X, d = - x sin 60^(@)` Therefore work done is `- Es sin 60^(@)` |
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