Formulas

Question 1

e

Answer 1

1.6×10^-¹⁹ C
[A¹T¹]

Question 2

Coulombs Law

Answer 2

F= kq1q2/r²
F= 1/4πεο q1q2/r²
[MLT^-²]

Question 3

K

Answer 3

= 1/4πεο = 9×10⁹ Nm²/C²
depends on medium
[ML³T-⁴A-²]

Question 4

If y depends on x, ymax =

Answer 4

dy/dx= 0

Question 5

dielectric Constant and relative permittivity

Answer 5

εο = 8.854×10^-¹² C²/Nm²
[M-¹L¹T⁴A²]
Er=Em/εο
Em = Er×εο
Fm= Fo/εr

Question 6

E

Answer 6

= lim q-0(F/q)
= 1/4πεο (q/r²)
N/C
[MLT-³A-¹]

Question 7

Dipole moment

Answer 7

P=2aq C-m
[LA¹T¹]

Question 8

E on axial line

Answer 8

= 1/4πεο 2P/r³

Question 9

E on equitorial line

Answer 9

= 1/4πεο P/r³
opposite direction than that of dipole

Question 10

Torque on dipole

Answer 10

τ = PEsinθ
τ = P×E
[ML²T-²]

Question 11

Potential energy of dipole

Answer 11

U = - PEcosθ
= P.E
[ML²T-²]

Question 12

Electric Flux

Answer 12

∅ = Edscosθ
= E.dS
[ML³T-³A-1]

Question 13

Gauss theorem ∅

Answer 13

Closed integral E.ds
E.dscos∅
If ∅=0
E.ds
E.A
For sphere,
1/4πεο q1q2/r² 4πr²
q/εο

Question 14

Linear, surface and volume charge density

Answer 14

λ = q/L
σ= q/A
ρ = q/V

Question 15

Field due to Infinitely long uniformly charged wire

Answer 15

E = λ/2πεοr

Question 16

E due to plane sheet made of charge v E due to plane sheet of conducting surface

Answer 16

σ/2εο
σ/εο because it has two sides two areas

Question 17

Electric Field due to a uniformly charged spherical shell ring
Outside
Inside
Surface
Where R is radius of shell

Answer 17

1/4πεo q/r² = σ/εo R²/r²
0
1/4εο q/R² = σ/εo