Electrostatic Potential And Capacitance Flashcards
What is the unit of electrostatic potential?
Volt (V)
True or False: Electrostatic potential is a scalar quantity.
True
Fill in the blank: The electrostatic potential due to a point charge is given by the formula _____.
V = k * Q / r
What does the symbol ‘k’ represent in the electrostatic potential formula?
Coulomb’s constant
What is the relationship between electric field (E) and electrostatic potential (V)?
E = -dV/dx
What is capacitance?
The ability of a system to store electric charge per unit voltage.
True or False: Capacitance depends on the voltage applied across the capacitor.
False
Fill in the blank: The capacitance of a parallel plate capacitor is given by the formula _____.
C = ε * A / d
What is the effect of increasing the distance between the plates of a capacitor on its capacitance?
Capacitance decreases.
What is a dielectric?
A material that increases the capacitance of a capacitor when placed between its plates.
True or False: The presence of a dielectric reduces the electric field between the plates of a capacitor.
True
How does the dielectric constant (κ) affect capacitance?
Capacitance increases by a factor of κ when a dielectric is introduced.
What is the formula for the energy (U) stored in a capacitor?
U = 1/2 C V^2
What is the relationship between charge (Q), capacitance (C), and voltage (V)?
Q = C * V
Fill in the blank: The total energy stored in a capacitor can also be expressed as _____ in terms of charge.
U = Q^2 / (2C)
What happens to the energy stored in a capacitor when the voltage is doubled?
The stored energy increases by a factor of four.
True or False: Capacitance is a property that depends on the geometry of the capacitor and the materials used.
True
What is meant by the term ‘breakdown voltage’ in capacitors?
The maximum voltage a capacitor can withstand before the dielectric fails.
True or False: Capacitors can store DC and AC voltages equally.
False
What is the primary function of capacitors in electronic circuits?
To store and release electrical energy.
Fill in the blank: The energy density (u) of an electric field is given by _____ per unit volume.
u = 1/2 εE^2
Work done by conservative force is what
-ΔU
Is electrostatic force conservative or non conservative and it’s work done is
Conservative
-ΔU
Work done by external agent slowly is
ΔU = W ext= k q qnot /r
What can you tell about sign of gravitational potential energy
Always negative ->
-Gm1m2/r
If r increase then U increase a and vice versa
What is value of k Coulomb’s constant
9 * 10^9 N m^2/C^2
Formula for finding number of pairs in a system of charges
n(n-1)/ 2
n= no. of charges
Define electrostatic potential and SI
Potential energy or work done per unit test charge
V= kq/r = U/q not = W/q not
J/C or Volts
What is electric field
Force per unit test charge or kq/r^2
Formula for zero potential of charges with ratio n
x=r/n+1 from small charge
x=r/n-1 from small charge where n = big/ small
Both points
Potential ke formula mein underoot n nhi ata
Formula of work done in term of potential
W ext = U = qnot * V
U is potential energy and V is potential
V = U/q not
Relationship between electric field and electric potential
Integrate V = - integrate E • dr
E = -dV/dr
What happens to potential along electric field
Decreases
What happens to potential in region where electric field is 0
Remain constant
In an electric field, a positive charge will move towards areas of _______.
lower potential
True or False: In an electric field, a negative charge moves from high to low potential.
False
What happens to potential energy (U) as a charge moves against the electric field?
Potential energy increases
What is the relationship between electric field E and force F?
E is the force per unit charge
F = qE
Fill in the blank: The electric field direction is defined as the direction a _______ charge would move.
positive
Formula for kinetic energy and potential energy related
Dec in U = inc in KI
V qnot = (1/2) m v^2
Electric potential due to ring with charge Q and radius R
Electric potential and electric field due to a ring at a distance x
Electric potential and field due to arc
V can also be k•lamda•alpha (with alpha in radian)
E and V for hollow (conducting, non conducting) and solid (conducting) sphere. For in,out and surface
E and V for solid non conducting in, out and surface
What is radius and potential of single big new drop formed from n drops with charge q
Torque of dipole
pE sin theta or p cross E
Potential energy of dipole, where is it max, min, 0
Electric potential due to dipole axial, equatorial and general point
What is the electric field inside a conducting material of an isolated conductor?
The electric field inside a conducting material of an isolated conductor is zero.
Is there excess charge inside a conductor?
There is no excess charge inside a conductor.
What is true about the potential of a conducting material?
The conducting material is equipotential.
E = 0 → Vconst.
What is true about the electric field on the surface of a conductor? And value
The electric field on the surface of the conductor is constant, irrespective of the shape. Which sigma/€not
Where sigma is surface charge density
When you connect 2 spherical conductors with radius R1 R2 and charge Q1 Q2, what is formula for finding new charge
Relationship between surface charge density and radius of curvature
Inversely proportional
What is electrostatic shielding
Process of a making a region free from any electronic field
Another name for capacitor
Condenser
SI of capacitor
Farad or Q/V which is coulomb/volt or coulomb^2/Joule
Formula for capacitor
C= Q/V
What does capacitance depend and not depend on
Depend- shape, size, geometry, A for area, d for distance, medium between plates or € not
Not depend on charge or voltage
How is E related to sigma
E = sigma/ €not = Q/A €not
V= E d
V= Qd/A €not
Force between 2 plates of capacitor formula
Intensity of electric field between plates of a charged capacitor depends on the distance between plates. True or false
False
3 formula each for energy stored in capacitor and work done by battery
How is potential, charge and capacitance related
Q=CV
Why is work done by battery more than the energy stored
Because half work goes into heat energy
Formula for energy density in capacitor
Formula for voltage and capicitance in series circuit
Total capacitance for circuit with 2 capacitor of value (3,6), (6,12),(4,12) —famous values
2,4,3
What remains same in capacitor circuit in series
Charge or Q
Formula for C and Q in parallel circuit of capacitor
What remains same in parallel circuit of capacitor
Voltage or V
What is the ration between Parallel and series combination of same n number of capacitors of identical capacitance
Cp/Cs= n^2 because
Cp=nc
Cs=c/n
What happens in short circuiting of a capacitor
V becomes 0 across a capacitor
What happens to potential and loss of energy (heat) when 2 capacitor joined through same terminal. Formula for V and U
V same
What happens to potential and loss of energy (heat) when 2 capacitor joined through opposite terminal. Formula for V and U
What is the potential at junction of 2 capacitor
What are dielectrics
Insulators which transfer electrical effect without conduction or moving- they can be polar or non polar
What is electric field inside dielectric or Einternal
What is E net with an electric field inside dielectric
What is the charge density and charge due to electric field inside dielectric, inside the dielectric
Relationship between C not and Capacitance after adding a dielectric k
Effect of dielectric wehen battery not connected on C, Q, V, E and U
Effect of dielectric wehen battery connected on C, Q, V, E and U
Formula for capacitance with a conducting slab
Formula for capacitor in series with different dielectric like this
Formula for capacitor in parallel with different dielectric like this
Capacitance formula for spherical capacitor
Capacitance formula for concentric spheres with outer earthed
What is the dipole of non polar dielectric
p=0
Capacitance formula for cylindrical capacitor
Same potential because charge flows from high potential to low potential
How is the electric field oriented in relation to the surface of a conductor?
The electric field is always perpendicular to the surface of the conductor.
