Question

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

• A. As shown in graph (a)
• B. As shown in graph (b)
• C. As shown in graph (c)
• D. As shown in graph (d)

Hint:

For conducting shells: \beginitemize • Electric field inside conductor = 0 • Field depends on net enclosed charge • Sudden jump in E occurs at charged surfaces \enditemize

Answer 1

The Correct Option is C

Step 1: Inside inner conducting shell: E = 0 (r < rA) 

Step 2: Between shells: E = (1)/(4πepsilon₀)(QA)/(r²) 

Step 3: Outside outer shell: E = (1)/(4πepsilon₀)((QA - QB))/(r²) Since |QB| > |QA|, field direction reverses. Thus graph (C) correctly represents variation of electric field.