Crack the Problem

Consider two situations:

1. A point charge q is placed at a distance d from a large conducting uncharged plate. The magnitude of the force experienced by q is R.
2. A point charge q is placed at a distance d each from the two perperdicular conducting uncharged large plates meeting at right angle. The magnitude of the force experienced by q is S.

Enter the numerical value of (S/R) where ( ) denotes the least integer function in the space provided at http://courses.manishverma.site/mod/quiz/view.php?id=433 .

Note: Only number(s) should be typed.

Cracked by:

• karthik vs
• Soumik Mukherjee

Answer: 1

Hint:

These types of problems are solved by the image method. A system of charge q at distance d from a plane metal sheet is replaced by a system of charge q with -q charge at distance 2d. In this method when the system is substituted by the charges, the potential at the plane originally occupied by the sheet must be zero.

When charge q is at distance d each from the two perpendicular metal sheets and if the system is replaced by q, -q and -q then the zero potential condition is not met. In this case the system should be replaced by q, -q, -q and a fourth charge q. The location of these three image charges is the same as the location of images when an object is placed in front of two mutually perpendicular mirrors and three images are formed.

(Edited by Manish Verma - Friday, 1 September 2006, 11:38 AM)