Why is the resultant electric field pointed like this?

AI Thread Summary
The discussion centers on the electric field generated by two charges, +4μC and -8μC, positioned 80mm apart. At point P, equidistant from both charges, the electric fields due to each charge are analyzed. The resultant electric field is not directed solely towards the -8μC charge because the -8μC charge exerts a stronger electric field, being twice the magnitude of the +4μC charge. This imbalance causes the resultant electric field to point slightly upwards and to the right, rather than directly horizontal. The positioning of point P below the line connecting the charges further clarifies this resultant direction.
curiousjoe94
Messages
21
Reaction score
0
Heres the question:

Two charges (one is +4μC, the other is -8μC). They lie on 80mm apart, so you can imagine that the +4μC charge is on the left and the -8μC is on the right. Point P is equidistant from the two charges, draw two arrows at P to represent the directions and relative magnitudes of the component of the electric field at P due to each of the charges. Hence draw an arow labelled R at P to represent the resultant electric field at P.


The main query I have is the resultant force bit of the question. Why is that the resultant force isn't just pointed horizontal towards the -8μC charge?

It says in the mark scheme that, ''If the two charges were equal in magnitude but opposite in sign the resultant electric field at P would be directed horizontally to the right. Since one charge is twice the other, the resultant is directed slightly upwards and towards the right.''

Why does the fact that the magnitude of one of the electric field is twice that of the other, cause the resultant to be altered from what 'should' be a straight-forward horizontal direction from charge +4μC to charge -8μC?
 
Physics news on Phys.org
It sounds like the point P doesn't lie on the line connecting the two charges.
 
vela said:
It sounds like the point P doesn't lie on the line connecting the two charges.

If that's the case, then it makes sense having point P lying below both those charges.
 
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Thread 'Variable mass system : water sprayed into a moving container'
Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
Back
Top