Electric Charges and Fields Practice Flashcards

Comprehensive practice flashcards covering basic electrostatics, Coulomb's Law, Electric Fields, Gauss's Law, and Charge Properties based on Chapter 1 physics lecture notes.

__________ deals with the study of forces, fields and potentials arising from static charges.

Electrostatics

Historically, the credit for discovering that amber rubbed with wool attracts light objects goes to __________.

Thales of Miletus

The word electricity is coined from the Greek word __________ meaning amber.

elektron

The property which differentiates the two kinds of charges is called the __________ of charge.

polarity

The American scientist __________ was the one to name the two kinds of charges as positive and negative.

Benjamin Franklin

A simple apparatus to detect charge on a body is the __________.

gold-leaf electroscope

Substances that allow electricity to pass through them easily are called __________.

conductors

Substances like glass, porcelain, plastic, and nylon that offer high resistance to the passage of electricity are called __________.

insulators

The property that the total charge of a system is the algebraic sum of all individual charges is known as __________ of charges.

additivity

The fact that all free charges are integral multiples of a basic unit of charge denoted by $e$ is termed as __________.

quantisation of charge

In the SI system, the basic unit of charge is the __________ and is denoted by the symbol $C$.

coulomb

The value of the basic unit of charge is approximately $e =$ __________.

$$1.602192 \times 10^{-19}\,C$$

The number of electrons in a charge of $-1\,C$ is approximately __________.

$$6 \times 10^{18}$$

The magnitude of the force ($F$) between two point charges $q_1$ and $q_2$ separated by distance $r$ in vacuum is given by the formula __________.

$$F = k \frac{q_1 q_2}{r^2}$$

In SI units, the value of the constant $k$ in Coulomb's law is about __________.

$$9 \times 10^9\,N\,m^2\,C^{-2}$$

The constant $\epsilon_0$ in the equation $k = \frac{1}{4\pi\epsilon_0}$ is called the __________.

permittivity of free space

The value of $\epsilon_0$ in SI units is __________.

$$8.854 \times 10^{-12}\,C^2\,N^{-1}\,m^{-2}$$

The principle that states the force on any charge due to a number of other charges is the vector sum of all the individual forces is the __________.

principle of superposition

The electric field $E$ produced by a charge $Q$ at a distance $r$ is given by the formula __________.

$$E = \frac{1}{4\pi\epsilon_0} \frac{Q}{r^2} \hat{r}$$

For a positive charge, the electric field is directed __________ from the charge.

radially outwards

Electrostatic field lines do not form any __________, which follows from the conservative nature of the electric field.

closed loops

Electric flux $\Delta\Phi$ through an area element $\Delta S$ is defined by the equation ___________.

$$\Delta\Phi = E \cdot \Delta S = E \Delta S \cos(\theta)$$

An electric dipole consists of a pair of equal and opposite point charges separated by a distance __________.

$$2a$$

The dipole moment vector $p$ has a magnitude of __________.

$$q \times 2a$$

The electric field of a dipole at large distances ($r \gg a$) falls off as __________.

$$1/r^3$$

The torque $\tau$ experienced by a dipole in a uniform external field $E$ is given by the vector product __________.

$$\tau = p \times E$$

The linear charge density $\lambda$ is defined as __________.

$$\Delta Q / \Delta l$$

Gauss's law states that the total electric flux through a closed surface $S$ equals __________.

$$q/\epsilon_0$$

The electric field magnitude $E$ due to an infinitely long straight uniformly charged wire at distance $r$ is __________.

$$E = \frac{\lambda}{2\pi\epsilon_0 r}$$

The electric field due to a uniformly charged thin spherical shell is __________ at all points inside the shell.

zero

The SI unit for surface charge density $\sigma$ is __________.

$$C/m^2$$