00:08
So let's start with the problem.
00:09
We have been given a problem where we have three negative point charges which lie at some distance from point p and we have to find the net electric field at point b.
00:22
Okay.
00:22
So let's start with the problem.
00:25
This is the figure that is given.
00:27
Okay.
00:28
So i'll tell i'll explain you three negative charges.
00:31
Okay.
00:32
And they are at distance.
00:33
Okay.
00:34
Only the distance from the second charge is given six and distance between the charge.
00:38
Is 8 okay so we have been told to find the net electric field at point p okay what will be the electric field and its direction okay so let's start with the problem i'll just represent this in a simple form okay so i'll just name the charges q1 okay charges will be q1 q2 q3 okay and electric fields corresponding electric fields will be e1, e2, e3.
01:08
Okay, we are taking in this direction.
01:09
I'll draw the figure, okay? so, the electric fields, i'll draw it, okay? these are the, this is q1, okay? this is q2, this is q3, okay? and this is point p, okay? okay, so electric field over here, this q, okay? since it's a negative charge, i'll tell you, in negative charge, what happens is the electric field is radially inverts okay it is inverse so this negative charge over here it will attract this p electric field will be towards q okay so like this here it will be like this here it will be like this okay so i'll just draw the things involved okay so electric field over here like this i'll make okay i'll just connect this points okay i'll use a different color okay, this i'll connect like this, okay? this points we will connect.
02:11
And corresponding distances also, i will write, okay? so distance is corresponding distance from the point p is r1, r2 and r3.
02:20
Okay, so this is r1, this is r2, and here it is r3, okay? and of this we know the value of r3.
02:28
R3 is equal to 6, okay? you can see here, it's given 6.
02:32
Okay, this is r in centimeter.
02:35
Please try to convert it in meter while using okay so now we will find the electric field okay so electric field over here will be like this okay so i'll just represent electric field will be like this even over here e2 and this will be e3 okay so it will be like this from p like this okay e1 e2 e3 okay so uh we will try to uh write them in terms of the horizontal and vertical components that is x and y okay so if you try to see e2 has only x component okay and e y we can resolve it okay so we will try to resolve okay and these are the electric field involved okay see e1 is like this e2 is like this and e3 is like this so we will resolve the components okay so this will be here it makes an angle 3 theta assume okay this will be even sign theta okay and here we will have one more component even cost theta okay similarly over here okay this will also be a theta okay so here it is e2 sorry e3 sine theta and towards here we will have one more e3 cost of theta okay so these are the things that are involved okay so we have to find e1, e2 and e3, okay? and then we have to write it, okay? so, in order to find the electric field, we know the formula is k, mod of q, that is magnitude of q, and magnitude of r square, okay? this is the formula, kq by r square, okay? so, we need the distance, r is the distance from charge to the point, okay? so we have to find water distance, r1, r3 and r2.
04:33
And also we need to find this theta okay so for that we will use the basic technometry okay so i'll just find the lens okay this is negative uh okay this is q1 q2 q 3 okay once we find this distances we just have to substitute okay so this is angle theta this is r1 you know this value is 6 and this value is 8 okay so can i write tan of theta is equal to 8 by 6 okay okay so tan inverse of 8x will be our theta, okay? so this theta is equal to 53 .1, okay, degree you can find.
05:14
And also, this is also 8 and this is also 6, okay? so we can find r1 is equal to, using pythagoras theorem if you find, r1 square is equal to 8 square plus 6 square, okay, this is equal to 100 square, not 100 square, this is equal to 100 actually...