Answer:
<h2>Magnitude of the second charge is

</h2>
Explanation:
According to columbs law;
F = 
F is the attractive or repulsive force between the charges = 12N
q1 and q2 are the charges
let q1 = - 8.0 x 10^-6 C
q2=?
r is the distance between the charges = 0.050m
k is the coulumbs constant =9*10⁹ kg⋅m³⋅s⁻⁴⋅A⁻²
On substituting the given values
12 = 9*10⁹*( - 8.0 x 10^-6)q2/0.050²
Cross multiplying

For a single slit illuminated with a 500 nm light gives a diffraction pattern on a far screen,the angle is mathematically given as
theta=25.3
Option A is correct
<h3> What angle does the 18th minimum occur?</h3>
Generally, the equation for the the angle is mathematically given as

Therefore

In conclusion
theta/7=16/5
theta=10*7/5
theta=25.3
Read more about Angle
brainly.com/question/14362353
b. describes it best because a form of molten cools down and makes igneous rock. Good luck! Please mark me brainliest!