Static & Direct Current Electricity (E1)

I=Current

t= time measured in seconds

q= charge in coulombs

When the value of one quantity increases with respect to decrease in other or vice-versa, then they are said to be inversely proportional. It means that the two quantities behave opposite in nature.

This means that as the distance ((r)) between the two charges increases, the force ((F)) decreases rapidly. Specifically, if the distance is doubled, the force is reduced to one-fourth of its original value. Conversely, if the distance is halved, the force increases to four times its original value. This inverse square relationship highlights how sensitive the force is to changes in distance between the charged objects.

When we talk about the force between two charges, we refer to Coulomb’s law, which states that the force ((F)) between two point charges

$$F=k\frac{q1q2}{r^2}$$

• (k) is Coulomb’s constant,

• (q_1) and (q_2) are the magnitudes of the charges,

• (r) is the distance between the charges.

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The sign of the force depends on the product of the charges (q_1) and (q_2):

• If both charges are of the same sign (both positive or both negative), the product (q_1 q_2) is positive, resulting in a repulsive force.

• If the charges are of opposite signs (one positive and one negative), the product (q_1 q_2) is negative, resulting in an attractive force.

So, when you have two unequal and opposite charges, the force between them is negative, indicating that the force is attractive. This means the charges will pull towards each other.

ε₀= permittivity of free space

D= Density

E= electric field strength