Home » Electrostatics
Category Archives: Electrostatics
Coulomb’s law
at each of the four corners of a sqare of side A, a charge +q is placed freely. what charge should be placed at the centre of the sqare so that whole system be in equilibrium
Asked Shashank
Share the knowledge
Electrostatics Concept Map and Question Bank
Electrostatics Concept Map
Download Electrostatics Question Bank, value based questions and HOTS
Value based questions from Electrostatics
Share the knowledge
Numerical from Electrostatics
Three point charged lie along the x axis in a vacuum: charge 1 in the middle, with charge 2 to the left, and charge 3 to the right. The magnitude of charge 1 is +3 microcoulomb, the magnitude of charge 2 is -4 microcoulomb, and the magnitude of charge 3 is -7 microcoulomb. The distance between charges 1 and 2 is 20 cm, while the distance between charges 1 and 3 is 15 cm. Determine the magnitude and direction of the net electrostatic force on charge 1.
Asked Tammy
Share the knowledge
A question from electric field
An insulating sphere of mass m and positive charge q is attached to a spring with length h and spring constant k and is at equilibrium. An infinitely long wire with positive linear charge density λ is placed a distance l away from the charged mass at equilibrium (note that the position of the top of the spring is fixed). The previous length of the spring was h. What is the new length of the spring in terms of h, q, k, λ, l as needed.
Share the knowledge
An interesting question from electrostatics
Two equal negative charge -q are fixed at the point (0,a) & (0,-a) on yhe y-axis. a positive charge Q is released from rest at the point (2a,0) on the x-axis. the charge Q will execute oscillatory motion how?
Asked Kritika
Share the knowledge
Capacitance, voltage and Potential difference
the capacity of parallel plate condenser is 5 micro Faraday. When a glass plate is placed between the plates of the conductor its potential become 1/8th of the original value. The value of dielectric constant will be
(A)1.6
(B)5
(C)8
(D)40
Answer:
The charge remains same
Share the knowledge
Why there is a 4(pi) in Coulomb’s law?
Why there is a 4π in Coulomb’s law?
Asked Rick Ghosh
Answer:
This is a consequence of geometry.
Please remember that Coulomb’s law is stated originally for point charges at rest. By symmetry, a point charge should exert equal force on a test charge at all points equidistant from it, which constitute a spherical shell of surface area 4πr2.
This consideration itself suggests the inverse square relation ship as well as the need for 4π.
That was actually my explanation for it.
The term 4π was not there when Coulomb’s law was first stated in cgs system. The term 4π was introduced in SI on rationalization of units based on Maxwell’s equations of electromagnetism.
But I feel that my earlier explanation is simple and convincing.
Hope you got it.
Further discussions are welcome.
Share the knowledge
Latest Posts
askphysics@Twitter
Ask Physics
@askphysics
- Magnetic effect(jee) https://t.co/5WXBHxr1a9
about 1 month ago