Two charges 4q and q are placed 30cm apart


Asked by admin @ in Physics viewed by 360 People


two point charges +4q and +q are placed 30cm apart.At what point on the line joining them the electric field is zero?

Answered by admin @



Where E=0 this point is called neutral point.
it is the point where electric field of both charge is same
we know tha t E=kQ/r^2
here k=1/4pi€
for 4q charge
let at ''a'' distance we get E=0 which is from q charge
so distance from 4q of 'a' point is 30-a
electric field by 4q charge on a is
E=k4q/(30-a)^2
electric field by q charge on a point
E=kq/a^2
both electric field are equal so put them equal
k4q/(30-a)^2=kq/a^2
solve this we get
4a^2=(30-a)^2
2a=30-a
3a=30
a=10
so at a distance 10cm from charge q we get E=0
distance from 4q charge 30-10=20cm.
i hope u got ur answer.
mark me as brainliest

Similar Questions

Two charges q1 and q2 are placed 30cm apart

Asked by admin @ in Physics viewed by 286 persons

Two charges q1 and q2 are placed 30cm apart. A third charge q3 is moved along the arc of a circle of radius 40cm frm C to D. The change …

A charge q is placed at 1 2 1

Asked by admin @ in Physics viewed by 409 persons

A charge q is placed at (1,2,1) and another charge -q is placed at (0,1,0) such that they form an electric dipole . There exists a uniform electric field E=2icap. …

A total charge q is broken in two parts

Asked by admin @ in Physics viewed by 307 persons

A total charge q is broken in two parts q1 and q2 and they are placed at a distance r from each other the maximum force of repulsion between them …

A certain charge q is divided into two parts

Asked by admin @ in Physics viewed by 358 persons

a certain charge Q is divided at first into two parts, q and Q-q.later on the charges are placed at a certain distance. if the force of interaction between the …

Two point electric charges of values q and 2q

Asked by admin @ in Physics viewed by 315 persons

⦁ Two point charges of values ‘q’ and ‘2q’ are kept at a distance ‘d’ apart from each other in air. A third charge ‘Q’ is to be kept along …

Two identical pith balls each carrying a charge q

Asked by admin @ in Physics viewed by 373 persons

Two identical pith balls,each carrying a charge q, are suspended from a common point by two strings of equal length ( L). FIND THE MASS OF EACH BALL. if the …

Two places a and b are 120 km apart

Asked by admin @ in Math viewed by 364 persons

two places a and b are 120 km apart from each other on highway. a car starts from a and another from b at the same time.if they move in …

Two small spheres each carrying a charge q

Asked by admin @ in Math viewed by 374 persons

2 small spheres each carrying a charge q are placed r m apart and they interact with a force f. if one of the sphere is taken around the oyher …

Two charged spheres are 8.45 cm apart

Asked by maham237 @ in Physics viewed by 455 persons

Two charged spheres are 8.45 cm apart. They are moved, and the force on each of them is found to have been tripled. How far apart are they now?

Five point charges each of charge q are placed

Asked by admin @ in Physics viewed by 313 persons

Five point charges each of charge q are placed on five vertices of regular hexagon of side l

Two point charges placed at a distance r

Asked by admin @ in Physics viewed by 368 persons

Two point charges placed at a certain distance r in air exert a force F on each other. Then the distance R at which these charges will exert the same …

Two point charges q1 and q2 are 3m apart

Asked by admin @ in Physics viewed by 282 persons

Two point charges Q1 and Q2 are 3m apart and the sum of charges is 10C. then find the values of Q1 and Q2 ​

Two identical point charges q each are kept 2m

Asked by admin @ in Physics viewed by 389 persons

Two identical point charges q each are kept 2m apart in air. A third point charges Q of unknown magnitude and sign is placed on the line joining the charges …

Equal charges q are placed at the four corners

Asked by admin @ in Physics viewed by 280 persons

Equal charges Q are placed at the four corners A, B, C, D of a square of length a. The magnitude of the force on the charge at B will …

Two equal positive charges q are fixed at points

Asked by admin @ in Physics viewed by 361 persons

Two equal positive charges q are fixed at point (a, 0) and (-a, 0) on x axis and opposite charge - q at rest is released from (0,a) on y-axis. …

Most viewed questions in Physics


Jeevandeep health and physical education std 10 answers pdf

Asked by admin @ in Physics viewed by 11082 persons


Hc verma physics class 9 solutions of describing motion

Asked by admin @ in Physics viewed by 2677 persons


How to leave nightmare land answer key

Asked by maham237 @ in Physics viewed by 1604 persons



Base area and stability of some objects with different shapes

Asked by admin @ in Physics viewed by 1537 persons


Which of the following statements about safe lifting are correct

Asked by admin @ in Physics viewed by 1524 persons


Porous water-absorbing mass of fibers

Asked by wiki @ in Physics viewed by 1502 persons



Absorption of water by filter paper is due to

Asked by admin @ in Physics viewed by 1443 persons


A composite wire of uniform diameter 3mm

Asked by admin @ in Physics viewed by 1412 persons


At a distance l 400m from the traffic light

Asked by admin @ in Physics viewed by 1347 persons



A rocket of mass m is launched straight up with thrust f⃗ thrust.

Asked by maham237 @ in Physics viewed by 1324 persons


Mind map for light reflection and refraction class 10

Asked by admin @ in Physics viewed by 1155 persons



A thief runs at a speed of 10m s

Asked by admin @ in Physics viewed by 1101 persons


A 5.8 x 10 4 watt elevator motor can lift

Asked by maham237 @ in Physics viewed by 1087 persons