Electric Fields: Definition, Properties, and Applications

Question 1

Gauss's law states that the electric flux through any closed surface is proportional to:

Accepted Answer

The net charge enclosed by the surface

Answer

The area of the surface

Answer

The permittivity of the medium

Answer

The electric field strength at the surface

Question 2

The electric field lines surrounding a positive point charge:

Accepted Answer

Start from the charge and extend to infinity

Answer

End at the charge and extend to infinity

Answer

Form closed loops around the charge

Answer

Intersect at the charge

Question 3

Which of the following is NOT a factor affecting the capacitance of a capacitor?

Accepted Answer

Frequency of the applied voltage

Answer

Plate area

Answer

Plate separation

Answer

Nature of the dielectric material

Question 4

The electric dipole moment of a system of point charges is a measure of:

Accepted Answer

The separation between the positive and negative charges

Answer

The total charge associated with the system

Answer

The strength of the electric field created by the system

Answer

The potential energy of the system

Question 5

How do you calculate the energy stored in an electric field using the electric field strength and the volume of the region where the field exists?

Accepted Answer

Energy stored = (1/2) * permittivity * electric field strength^2 * volume

Answer

Energy stored = (1/2) * electric field strength * volume

Answer

Energy stored = permittivity * electric field strength * volume

Answer

Energy stored = (1/2) * permittivity * electric field strength^2

Question 6

Which of the following accurately describes the characteristics of electric field lines?

Accepted Answer

Electric field lines indicate the direction of the electric field at a given point.

Accepted Answer

Electric field lines are perpendicular to surfaces of equal electric potential.

Answer

Electric field lines are always straight.

Answer

Electric field lines only start from positive charges and end on negative charges.

Question 7

According to Gauss's law, the electric flux through a closed surface is directly proportional to the:

Accepted Answer

charge enclosed by the surface

Answer

area of the surface

Answer

permittivity of the medium

Answer

strength of the electric field

Question 8

A capacitor stores electrical energy in the form of:

Accepted Answer

an electric field

Answer

a magnetic field

Answer

chemical energy

Answer

thermal energy

Question 9

In a series circuit, the current:

Accepted Answer

is the same throughout the circuit

Answer

is different at different points in the circuit

Answer

is inversely proportional to the resistance of the circuit

Answer

is directly proportional to the voltage across the circuit

Question 10

In a parallel circuit, the voltage:

Accepted Answer

is the same across all branches of the circuit

Answer

is different in different branches of the circuit

Answer

is inversely proportional to the current in the circuit

Answer

is directly proportional to the resistance of the circuit

Question 11

The power dissipated in a resistor is:

Accepted Answer

equal to the product of current and voltage

Answer

equal to the square of the current

Answer

equal to the square of the voltage

Answer

independent of the resistance

Question 12

The root mean square (rms) value of an alternating current (AC) is:

Accepted Answer

equal to the peak value divided by √2

Answer

equal to the average value of the AC

Answer

equal to the maximum value of the AC

Answer

greater than the peak value of the AC

Question 13

An electron is initially at rest in a uniform electric field. What is the nature of its motion?

Accepted Answer

The electron accelerates in the direction of the electric field.

Answer

The electron moves with constant velocity in the direction of the electric field.

Answer

The electron moves with constant acceleration in the direction opposite to the electric field.

Question 14

An electric field with a magnitude of 2 × 10^3 V/m is applied to a point charge of -4 μC. What is the force experienced by the charge?

Accepted Answer

-8 μN

Answer

8 μN

Answer

8 mN

Answer

-8 mN

Question 15

Which of the following is the unit for electric field strength?

Accepted Answer

Volt per meter

Answer

Coulomb

Answer

Newton per coulomb

Answer

Farad

Question 16

An electron is released from rest in a uniform electric field. The electron will experience:

Accepted Answer

Constant acceleration in the direction of the field.

Answer

Constant velocity in the direction of the field.

Answer

Zero acceleration.

Answer

Periodic motion.

Question 17

Which of the following materials is a good conductor of electricity?

Accepted Answer

Metal

Answer

Rubber

Answer

Wood

Answer

Glass

Question 18

Gauss's law states that the electric flux through a closed surface is proportional to the:

Accepted Answer

Net charge enclosed by the surface

Answer

Area of the surface

Answer

Electric field strength at the surface

Answer

Potential difference across the surface

Question 19

An electric field is uniform if its:

Accepted Answer

Magnitude and direction are constant throughout the region.

Answer

Magnitude is constant but the direction is not.

Answer

Direction is constant but the magnitude is not.

Answer

Magnitude is zero everywhere.

Question 20

Which of the following is NOT an application of electric fields?

Accepted Answer

Magnetic resonance imaging

Answer

Electric motors

Answer

Capacitors

Answer

Electrostatic precipitators

Question 21

The electric field within a conductor is:

Accepted Answer

Zero

Answer

Non-zero and uniform

Answer

Non-zero and non-uniform

Answer

Dependent on the conductor's shape

Question 22

The SI unit of electric field strength is the:

Accepted Answer

Newton per Coulomb

Answer

Volt

Answer

Coulomb

Answer

Farad

Question 23

Which of the following statements about electric fields is incorrect?

Accepted Answer

Electric fields are influenced by magnetic fields.

Answer

Electric fields are non-conservative.

Answer

Electric fields can exert forces on charged particles.

Answer

Electric fields can be shielded by conductors.

Question 24

Gauss's law relates the electric flux through a closed surface to the:

Accepted Answer

Enclosed charge

Answer

Electric field strength

Answer

Voltage difference

Answer

Capacitance

Question 25

Which of the following materials is a good conductor of electricity?

Accepted Answer

Copper

Answer

Rubber

Answer

Glass

Answer

Wood

Question 26

What is the direction of the electric field inside a uniformly charged spherical shell?

Accepted Answer

Zero

Answer

Towards the center

Answer

Away from the center

Answer

Random

Question 27

What kind of electric field exists between two oppositely charged parallel plates?

Accepted Answer

Uniform

Answer

Non-uniform

Answer

Zero

Answer

Random

Question 28

What is the nature of the force between two point charges of the same magnitude and sign?

Accepted Answer

Repulsive

Answer

Attractive

Answer

Zero

Answer

Random

Question 29

Which of the following statements about electric fields accurately describes their force-field nature?

Accepted Answer

Electric fields exert forces on charged particles.

Answer

Electric fields are always uniform.

Answer

Electric fields are non-conservative force fields.

Answer

Electric fields are not force fields.

Question 30

Gauss's law mathematically relates electric flux and charge. Which of the following correctly states this relationship?

Accepted Answer

The electric flux through any closed surface is proportional to the net charge enclosed by the surface.

Answer

The electric field is inversely proportional to the square of the distance from the source charge.

Question 31

The electric field 'E' at a distance 'r' from a point charge 'q' is given by a mathematical expression. Which of the following options represents this expression accurately?

Accepted Answer

E = k * q / r^2

Answer

E = k * q * r^2

Answer

E = q * k / r^3

Answer

E = q / k * r^2

Question 32

When an electron, a negatively charged particle, is placed in an electric field, the direction of the force it experiences relative to the field's direction is:

Accepted Answer

Opposite to the electric field's direction.

Answer

Parallel to the electric field's direction.

Answer

The force is zero.

Answer

Perpendicular to the electric field's direction.

Question 33

Which of the following materials is a conductor of electricity, allowing for the flow of electric current?

Accepted Answer

Copper

Answer

Wood

Answer

Rubber

Answer

Glass

Question 34

Capacitors, electronic components, store energy in the form of:

Accepted Answer

Electric energy

Answer

Thermal energy

Answer

Mechanical energy

Answer

Light energy

Question 35

The breakdown voltage of a dielectric material, a critical value related to its insulating properties, is defined as:

Accepted Answer

The maximum voltage that can be applied without causing the material to become conductive.

Answer

The voltage at which the material reaches its maximum capacitance.

Answer

The minimum voltage that can be applied to cause the material to become conductive.

Question 36

Electrostatic precipitators are a practical application of electric fields. What is their primary purpose?

Accepted Answer

Removing particulate matter from gases.

Answer

Modifying mechanical gear ratios

Answer

Generating electricity from mechanical motion

Answer

Transmitting hydraulic power

Question 37

The potential difference between two points in an electric field represents:

Accepted Answer

The electrical potential energy difference per unit charge between the points.

Answer

The electric field strength at those points.

Answer

The force per unit charge at those points.

Question 38

A positive point charge is placed in a uniform electric field. What is the direction of the electric force acting on the charge?

Accepted Answer

In the same direction as the electric field.

Answer

Opposite to the direction of the electric field.

Answer

Perpendicular to the direction of the electric field.

Answer

The force is zero.

Question 39

A hollow conducting sphere carries a net charge of +Q. What is the electric field inside the sphere?

Accepted Answer

Zero

Answer

Uniform and directed radially outward.

Answer

Uniform and directed radially inward.

Answer

Non-uniform and directed radially outward.

Question 40

A charged rod is brought near an uncharged metal sphere. What happens to the sphere?

Accepted Answer

The sphere will be polarized, with opposite charges accumulating on the surface closest to the rod.

Answer

The sphere will become a conductor.

Answer

The sphere will remain neutral and no charges will redistribute.

Answer

The sphere will acquire a net charge of the same sign as the rod.

Question 41

Which of these materials exhibits the highest electrical conductivity?

Accepted Answer

Copper

Answer

Plastic

Answer

Wood

Answer

Rubber

Question 42

An electron is situated within an electric field of 1000 N/C. Determine the magnitude of the force acting on the electron.

Accepted Answer

1.6 x 10^-16 N

Answer

1.6 x 10^-10 N

Answer

1.6 x 10^-13 N

Answer

1.6 x 10^-19 N

Question 43

Two points within an electric field have a potential energy difference of 10 J. What is the potential difference between these points?

Accepted Answer

10 V

Answer

0.1 V

Answer

1 J

Answer

100 V

Question 44

According to Gauss's law, the total electric flux passing through a closed surface is directly proportional to what?

Accepted Answer

The total charge enclosed by the surface

Answer

The electric field at the surface

Answer

The area of the surface

Answer

The permittivity of the medium inside the surface

Question 45

What is an electric field line?

Accepted Answer

A line that indicates the direction of the force exerted on a positive charge.

Answer

A line representing the electric potential at a given point.

Answer

A line connecting two opposite charges.

Question 46

Calculate the electric potential at a point situated 0.1 m away from a point charge of 10 μC.

Accepted Answer

9 x 10^3 V

Answer

9 x 10^12 V

Answer

9 x 10^9 V

Answer

9 x 10^6 V

Question 47

Two point charges of equal magnitude but opposite signs are separated by a distance of 0.2 m. What is the electric field strength at the midpoint between the charges?

Accepted Answer

0 N/C

Answer

7.2 x 10^3 N/C

Answer

1.8 x 10^3 N/C

Answer

3.6 x 10^3 N/C

Question 48

A dielectric material with a relative permittivity of 4 is subjected to an electric field of 1000 N/C. Determine the displacement field within the material.

Accepted Answer

4000 N/C

Answer

1000 N/C

Answer

2500 N/C

Answer

9000 N/C

Question 49

For a given volume, which of these shapes exhibits the highest capacitance?

Accepted Answer

Sphere

Answer

Cube

Answer

Parallel plates

Answer

Cylinder

Question 50

Calculate the energy stored in a capacitor with a capacitance of 10 μF and a voltage of 100 V.

Accepted Answer

500 mJ

Answer

50 mJ

Answer

5 J