Electric intensity is equal to :
- time rate of change of potential
- minimum rate of change of potential with distance
- maximum rate of change of potential with distance
- none of the above.
The Correct Option is C
Approach Solution - 1
Approach Solution -2
Ans. Mathematically, an electric field at a point in space is a vector field defined as the electrostatic force per unit charge exerted on a small unit positive charge at that point. The formula of the electric field is given by
E=F/q
Where
- E = Electric field intensity due to a point charge
- q = test charge
- F = Force experienced by the test charge due to the point charge
Consider two ‘point’ charges Q and q placed in a system, r distance apart. The charge Q exerts a force on charge q as per Coulomb’s Law, given by
F = 1/4πε0 (Qq)/r2
To validate the fact that the force acts irrespective of whether the charge q is placed or not in the system, the concept of ‘Field’ was established. According to this, we say that the charge Q emits an electric field everywhere around it and when another charge q is brought into the system, it acts on it to produce a force.
Hence, the electric field due to a point charge Q at distance r is given by
E = 1/4πε0 (Q)/r2
From the above equation,
- It can be inferred that, if the magnitude of q is considered unity, i.e., 1 then the Force F becomes equal to the Electric Field E generated by the charge Q itself.
- Thus, Electric Field E due to a charge Q at a point can be described as the force a unit positive charge would experience if placed at that point.
- Here, Q is called the source charge while any other charge q placed in the vicinity to test the effects of the source is called a test charge.
- Electric field intensity is a vector quantity and its SI unit is Newton per Coulomb (NC-1).
- The dimensional formula of the electric field is [MLT-3A-1]
Top Questions on electrostatic potential and capacitance
- A 5-ohm resistor is connected to a 10 V battery. Calculate the current flowing through the resistor.
- MHT CET - 2025
- Physics
- electrostatic potential and capacitance
- Two point charges \( +4 \, \mu\text{C} \) and \( -2 \, \mu\text{C} \) are separated by a distance of 0.3 m in air. What is the magnitude of the electrostatic force between them?
- MHT CET - 2025
- Physics
- electrostatic potential and capacitance
- Three infinitely long wires with linear charge density \( \lambda \) are placed along the x-axis, y-axis and z-axis respectively. Which of the following denotes an equipotential surface?
- JEE Main - 2025
- Physics
- electrostatic potential and capacitance
- A wire of resistance R is bent into an equilateral triangle and an identical wire is bent into a square. The ratio of resistance between the two end points of an edge of the triangle to that of the square is:
- JEE Main - 2025
- Physics
- electrostatic potential and capacitance
- Two capacitors \( C_1 \) and \( C_2 \) are connected in parallel to a battery. Charge-time graph is shown below for the two capacitors. The energy stored with them are \( U_1 \) and \( U_2 \), respectively. Which of the given statements is true?
- JEE Main - 2025
- Physics
- electrostatic potential and capacitance
Concepts Used:
Electrostatic Potential and Capacitance
Electrostatic Potential
The potential of a point is defined as the work done per unit charge that results in bringing a charge from infinity to a certain point.
Some major things that we should know about electric potential:
- They are denoted by V and are a scalar quantity.
- It is measured in volts.
Capacitance
The ability of a capacitor of holding the energy in form of an electric charge is defined as capacitance. Similarly, we can also say that capacitance is the storing ability of capacitors, and the unit in which they are measured is “farads”.
Read More: Electrostatic Potential and Capacitance
The capacitor is in Series and in Parallel as defined below;
In Series
Both the Capacitors C1 and C2 can easily get connected in series. When the capacitors are connected in series then the total capacitance that is Ctotal is less than any one of the capacitor’s capacitance.
In Parallel
Both Capacitor C1 and C2 are connected in parallel. When the capacitors are connected parallelly then the total capacitance that is Ctotal is any one of the capacitor’s capacitance.