Two concentric conducting thin spherical shells A and B having radii rA and rB(rBrA) are charged to QA and -QB( |QB| |QA|). The electrical field along a line. (passing through the center) is :

Question

Two concentric conducting thin spherical shells A and B having radii rA and rB(rB>rA) are charged to QA and -QB( |QB|> |QA|). The electrical field along a line. (passing through the center) is : (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

As charge on shell B is negative so, potential inside B is constant and negative. Also due to positive charge, potential inside A is positive and constant and greater than that of B. Therefore, as r increases potential decreases and as rA is crossed, potential becomes negative. At the surface of shell B, it is more negative. This variation is represented in graph (c). This problem is considered as wrong, because question asked is for field and graphs are given by potential.

Q. Two concentric conducting thin spherical shells A and B having radii rA​ and rB​(rB​>rA​) are charged to QA​ and −QB​(∣QB​∣>∣QA​∣). The electrical field along a line. (passing through the center) is :

Q. Two concentric conducting thin spherical shells $A$ and $B$ having radii $r_{A}$ and $r_{B} (r_{B} > r_{A})$ are charged to $Q_{A}$ and $- Q_{B} (∣ Q_{B} ∣ > ∣ Q_{A} ∣)$ . The electrical field along a line. (passing through the center) is :