Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 12-science Answered

 01---- A parallel plate air capacitor is connected to a battery. The quantities charge, voltage, electric field, and energy associated with this capacitor are given by Q0, V0, E0 and U0 respectively. A dielectric slab is now introduced to fill the space between the plates with battery still in connection. The corresponding quantities are now given by Q, V, E and U are related to previous quantities as (a) Q> Q0 (b) V> V0 (c) E> E0 (d) U> U0 
 
02---A parallel plate air capacitor with no dielectric between the plates is connected to the constant voltage source. How would capacitance and charge change if dielectric of dielectric constant K=2 is inserted between the plates. C0 and Q0 are the capacitance and charge of the capacitor before the introduction of the dielectric. (a) C=C0/2 ; Q=2Q0 (b) C=2C0 ; Q=Q0/2 (c) C=C0/2 ; Q=Q0/2 (d) C=2C0 ; Q=2Q0
Asked by shreeshampandey | 19 Nov, 2015, 11:50: AM
answered-by-expert Expert Answer

The potential difference 'V' between the plates remains unchanged (i.e., equal to the voltage of the battery) because the capacitor 'C' remains connected to the battery.

i.e., C = KC0

Thus, V = V0.

The introduction of the dielectric slab increases capacitance C. Hence, Q (= CV) increases.

Q = CV = (KC0)V0 = KQ0

As K>1, Q>Q0.

Since the plate separation ‘d’ remains unchanged, V remains unchanged and electric field, begin mathsize 14px style straight E equals straight V over straight d end styleremains unchanged.
begin mathsize 14px style therefore straight E equals straight V over straight d equals straight V subscript 0 over straight d equals straight E subscript 0 end style

i.e., E = E0

begin mathsize 14px style therefore end styleThe energy stored, begin mathsize 14px style straight U equals 1 half CV squared end style increases because 'C' increases.
begin mathsize 14px style straight U equals 1 half CV squared space space space equals 1 half left parenthesis KC subscript 0 right parenthesis left parenthesis straight V subscript 0 right parenthesis squared space space space equals KU subscript 0 end style
 
As, K>1, U>U0.
Hence, option (a) and (d) are correct.

Note: Kindly ask the other question as a separate query.
Answered by Faiza Lambe | 19 Nov, 2015, 02:06: PM
CBSE 12-science - Physics
Asked by dasrituparna1999 | 13 Apr, 2024, 06:56: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by bmahalik21 | 05 Mar, 2023, 08:23: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by s3043632 | 22 Jan, 2023, 06:45: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by priyr7687 | 28 Jun, 2022, 06:19: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by tahseenaamir07 | 25 Jun, 2022, 01:33: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Asked by ekanathtanpure77 | 23 Jun, 2022, 07:56: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
Get Latest Study Material for Academic year 24-25 Click here
×