question_answer

Three identical point charges, as shown are placed at the vertices of an isosceles right angled triangle. Which of the numbered vectors coincides in direction with the electric field at the mid-point M of the hypotenuse                                                                                                            [AMU 2000]

A)            1    

B)            2

C)            3    

D)            4

Correct Answer: B

Solution :

                     \[{{E}_{A}}\] = Electric field at M due to charge placed at A \[{{E}_{B}}\]= Electric field at M due to charge placed at B \[{{E}_{C}}\] = Electric field at M due to charge placed at C As seen from figure \[|\overrightarrow{{{E}_{B}}}|\,=\,|\overrightarrow{{{E}_{C}}}|,\] so net electric field at M, \[{{E}_{net}}={{E}_{A}};\] in the direction of vector 2.