Rationalised 2023-24
Physics
78
12 The energy U stored in a capacitor of capacitance C, with charge Q and
voltage V is
U
QV
CV
Q
C
=
=
=
21
21
1
2
2
2
The electric energy density (energy per unit volume) in a region with
electric field is (1/2)e0E2 Physical quantity
Symbol
Dimensions
Unit
 Remark
Potential
 or V
[M1 L2 T–3 A–1]
V
Potential difference is
physically significant
Capacitance
C
[M–1 L–2 T–4 A2]
F
Polarisation
P
[L–2 AT]
C m-2
Dipole moment per unit
volume
Dielectric constant
K
[Dimensionless]
POINTS TO PONDER
1 Electrostatics deals with forces between charges at rest