Two point charges of opposite sign are brought close together. Which statement best describes the field lines of the combined point charges?

(Points : 1)
The field lines from the positive charge point toward the negative charge.

The field lines from the positive charge point away from the negative charge.

The field lines from both charges cross each other in the middle.

The field lines of both charges point away from each other.

Question 6.6. Which of the following would be true if a test charge were negative instead of positive? (Points : 1)
The field lines of negative source charges would point inward.
The field lines of negative source charges would point outward.
The field lines would stay exactly the same.
The field lines would disappear.

Question 7.7. An electric field is measured at 3.00 × 105 N/C at a distance from a source point charge of 3.00 × 106 C. How far is the point from the source charge?
(Points : 1)
0.09 m

0.30 m

0.36 m

0.60 m

-towards negative charge

-point inward
-??

Question 6.6: Which of the following would be true if a test charge were negative instead of positive?

To determine the effect of a negative test charge on the electric field, we need to consider the behavior of negative charges in an electric field. Negative charges are attracted to positive charges, so the field lines of negative charges would point inward.

Therefore, the correct answer is:

The field lines of negative source charges would point inward.

Question 7.7: An electric field is measured at 3.00 × 105 N/C at a distance from a source point charge of 3.00 × 106 C. How far is the point from the source charge?

To solve this problem, we can use Coulomb's Law, which states that the electric field strength is equal to the force experienced by a test charge divided by the magnitude of the test charge.

The equation for electric field strength is given by:

E = k * q / r^2

where E is the electric field strength, k is the Coulomb's constant (9.0 x 10^9 N•m^2/C^2), q is the charge, and r is the distance from the source charge.

Given that the electric field strength (E) is 3.00 × 10^5 N/C and the source charge (q) is 3.00 × 10^6 C, we can rearrange the equation to solve for the distance (r):

r = sqrt(k * q / E)

Plugging in the values:

r = sqrt((9.0 x 10^9 N•m^2/C^2) * (3.00 × 10^6 C) / (3.00 × 10^5 N/C))

Calculating this expression will give us the distance (r).

After the calculations, we find:

r = 0.30 m

Therefore, the correct answer is:

0.30 m