Two point charges are located on the y-axis as follows: charge = −1.50 nc at y = −0.60 m, and charge = +3.20 nc at the origin (y = 0). what is the total force (magnitude and direction) exerted by these two charges on a third charge = +5.00 nc located at y = −0.40 m.

The force exerted on Q3 has a magnitude of 7.8662*^10-7 N and it goes down the Y axis.

F = -7.8662*10^-7 N

Explanation:

What you need to now?

Coulombs law :  

F12 = k*(q1*q2)/ r^2   --> the force particle 1 makes to the particle 2

k = 8.99*10^9 N*m^2 / C^2  --> this is a constant

First of all you have to convert the units to th SI,

nano= 10^-9

Q1 or Charge 1 = -1.50nC = -1.50*(10^-9) C

Q2 or Charge 2 =  3.20nC = 3.20*(10^-9) C

Q3 or Charge 3 = 5nC = 5*(10^-9) C

Then you have to do your diagram as you see at the bottom, take into account :

like charges repel each other,  alike charges  attract each other.

Let's find the distance between the particles :

R32 = 0.4 m

R31 = 0.2 m

Now we apply Coulombs law  for every charge that exerts  a force to Q3 as follows:

F23 = k*(Q2*Q3)/ (R23)^2 , we replace the data we already have an we find:

F23 = 8.99*10^-7 N

F13 = k*(Q1*Q3)/ (R31)^2 , we replace the data we already have an we find:

F13 = -1.685*10^-6 N

Now you have to sum the forces and find the total force exerted on Q3

Sum F = F23 + F13

F = -7.8662*10^-7 N

The force exerted on Q3 has a magnitude of 7.8662*^10-7 N and it goes down the Y axis.

^  Y

l

l   o   --> Q2 = 3.2 nC   at y=0

l

l  

l

l   o  -->  Q3 = 5 nC  at y = -0.4m

l  l        l

l v        l

l F13   v

l         F23

l   o  --> Q1 = -1.50 nC at y = - 0.6m

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia