[2008EM/HMW-05]

IMSc-IV Physics-IV : Electricity and Magnetism Jan-Apr 2008 MM : 20 Set-V : Group Activity-II Electric Field and Electric Potential

• Figure below shows four nonconducting rods, two straight and two circular, each has a uniform charge density of {\it magnitude} $\sigma$ as shown in the figure. For each case what is the direcion of the net electric field at a point $P$. 
• Four nonconducting rods, in shape of circular arcs of the same radius, subtend an angle $\alpha$ at the center and have uniformly distributed total charge as given below.
  1. Total Charge $=+8Q,\quad \alpha=30^{\mbox{o}}$
  2. Total Charge $=+2Q, \quad\alpha=90^{\mbox{o}}$
  3. Total Charge $=+4Q,\quad \alpha=60^{\mbox{o}} $ 
  4. Total Charge $=+5Q, \quad\alpha=120^{\mbox{o}}$
  Rank the rods according to their charge densities in the order of increasing charge density.
• [$\oslash$] Discuss the following questions from H.C.Verma, Vol-II, giving a short explanation for your answer in each case.
• Questions (1)-(9) in "OBJECTIVE-I" on page 119-120 and find correct answers giving your reasons in each case.
• Questions (3) and (10) in "QUESTIONS FOR SHORT ANSWER" on page 119.
• Questions (3), (5) and(7) from "OBJECTIVE II" on page 120.