Question 1

Which of the following best describes a scalar field in physics?

Accepted Answer

A field that assigns a scalar value to every point in space.

Question 2

The electric field $$\vec{E}$$ produced by a point charge $$q at a $$distance $$r in $$vacuum is given by which equation?

Accepted Answer

$$\vec{E} = \frac{q}{4\pi\$$epsilon_0$$ r^2$} \hat{r}$$

Question 3

If four identical negative charges are placed at the corners of a square, what is the electric field at the center of the square?

Accepted Answer

It is zero.

Question 4

Which statement about electric field lines is correct?

Accepted Answer

Field lines never cross.

Question 5

A proton and an electron are separated by a distance $$r. $$What is the magnitude of the electric field at the position of the electron due to the proton?

Accepted Answer

$$E = \frac{e}{4\pi\$$epsilon_0$$ r^2$}$$

Question 6

Which of the following is NOT a property of electric field diagrams?

Accepted Answer

The field exists only at the points shown in the diagram.

Question 7

If two equal and opposite charges are fixed along the x-axis, what is the direction of the electric field at a point on the perpendicular bisector?

Accepted Answer

Along the y-axis.

Question 8

The electric field at a point due to multiple charges is calculated by:

Accepted Answer

Adding the fields from each charge vectorially.

Question 9

What is the electric field at a distance $$L$$ from the center of a dipole along the perpendicular bisector?

Accepted Answer

$$E = \frac{p}{4\pi\$$epsilon_0$$ L^3$}$$

Question 10

Which of the following best explains the difference between Newton's and Faraday's view of forces?

Accepted Answer

Newton believed in action at a distance, Faraday believed forces are mediated by fields.

Question 11

A test charge $$q' is $$placed in an electric field $$\vec{E}. $$What is the force experienced by the test charge?

Accepted Answer

$$\vec{F} = q' \vec{E}$$

Question 12

Which real-world scenario best illustrates the concept of a vector field?

Accepted Answer

Wind speed and direction across a city.

Question 13

If the electric field strength near the earth's surface is $$10^2 to$$ $$10^4 N/C$$, what is the field strength inside an atom?

Accepted Answer

$$10^{11} N/C$$

Question 14

Which of the following statements about electric dipoles is correct?

Accepted Answer

The net charge of a dipole is zero.

Question 15

In unit vector notation, what does $$\hat{r}$$ represent in the electric field equation?

Accepted Answer

The direction from the source charge to the point of interest.

Question 16

If a charge $$A$$ moves, how long does it take for the force vector on charge $$B to $$respond by changing direction?

Accepted Answer

After a finite time, as changes in the field propagate at the speed of light.

Question 17

Which property of field lines indicates the magnitude of the electric field?

Accepted Answer

The density (spacing) of the lines.

Question 18

A charged particle is located at the origin. What is the direction of the electric field at a point (1,0) cm if the charge is negative?

Accepted Answer

Towards the origin.

Question 19

Which equation correctly relates the gravitational field strength $$g to $$mass $$m$$ and distance $$r$$?

Accepted Answer

$$g \propto m / r^2$

Study Notes: The Electric Field (Chapter 23, PHYA22-2026)

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