# A dipole is at the centre of a non conducting surface.If magnitudeof electric field at certain point on the surface is 10N/C,the which of the following cannot be the magnitude of electric field(in N/C)anywhere on the surface of the shpere? a)4 b)8 c)16 d)32

Aman Bansal
592 Points
11 years ago

Dear Manik,

The key to solving this question is applying Gauss Law through drawing Gaussian surfaces. The example in your book probably reached the result you give by drawing a cylinder perpendicularly through a charged sheet. If not, see the explanation here under the section "Field of an Infinite Plane Sheet of Charge". You need to understand how exactly this gives you the result E=σ2?0

For this particular geometry, the following Gaussian surfaces should be used:

The red rectangle is the surface you should use to find the field at A. The two green rectangles should be used to find the field at B. And the two blue rectangles should be used to find the field at C. Note that each rectangle in fact represents a cylindrical Gaussian surface.

Cracking IIT just got more exciting,It s not just all about getting assistance from IITians, alongside Target Achievement and Rewards play an important role. ASKIITIANS has it all for you, wherein you get assistance only from IITians for your preparation and win by answering queries in the discussion forums. Reward points 5 + 15 for all those who upload their pic and download the ASKIITIANS Toolbar, just a simple  to download the toolbar….

So start the brain storming…. become a leader with Elite Expert League ASKIITIANS

Thanks

Aman Bansal

27 Points
11 years ago

options c and D