Test Index

NCERT Class XII Chapter
Electric Charges and Fields
Questions With Solutions

© examsnet.com
Question : 7 of 34
Marks: +1, -0
(a) An electrostatic field line is a continuous curve. That is, a field line cannot have sudden breaks. Why not?
(b) Explain why two field lines never cross each other at any point?
Solution:  
As, FOA→F_{\overrightarrow{OA}} = - FOC→F_{\overrightarrow{OC}} or FOA→F_{\overrightarrow{OA}} + FOC→F_{\overrightarrow{OC}} = 0 ... (i)
So, the net force on charge of + 1 μC at O is
F→\overrightarrow{F} = FOA→F_{\overrightarrow{OA}} + FOB→F_{\overrightarrow{OB}} + FOC→F_{\overrightarrow{OC}} + FOD→F_{\overrightarrow{OD}} or F→\overrightarrow{F} = 0
A field line cannot have sudden breaks because the moving test charge never jumps from one position to the other.
(b) Two field lines never cross each other at any point, because if they do so, we will obtain two tangents pointing in two different directions of electric field at a point, which is not possible.
© examsnet.com
Go to Question:
Prev Question
Next Question