JEE Main202524 Jan 2025Morning ShiftPhysicsCapacitanceActual
A parallel plate capacitor was made with two rectangular plates, each with a length of l=3 ~cm and breath of b =1 ~cm . The distance between the plates is 3 ~m . Out of the following, which are the ways to increase the capacitance by a factor of 10 ? A. l=30 ~cm , ~b =1 ~cm , ~d =1 ~m B. l=3 ~cm , ~b =1 ~cm , ~d =30 ~m C. l=6 ~cm , ~b =5 ~cm , ~d =3 ~m D. l=1 ~cm , ~b =1 ~cm , ~d =10 ~m E. l=5 ~cm , ~b =2 ~cm , ~d =1
Options
- AA only
- BC only
- CB and D only
- DC and E only
Correct answer
D. C and E only
Step-by-step solution
We know C= A ₀ d = b ₀ d So to increase the capacitance by 10 factor ( A d ) has to increase by 10 fator. For option (A) C^ = (30 ) b ₀ ( d 3 ) =30 C For option (B) C^ = b ₀ 10 d = C 10 For option (C) C^ = (2 ) 5 b ₀ d =10 C For option (D) C^ = ( 3 ) b ₀ ( 10 d 3 ) = C 10 For option (E) C^ = ( 3 ) 5(2 b) ₀ ( d 3 ) =10 C Clearly (C) and (E) are the situation for 10 C