# NTNUJAVA Virtual Physics LaboratoryEnjoy the fun of physics with simulations! Backup site http://enjoy.phy.ntnu.edu.tw/ntnujava/

## Easy Java Simulations (2001- ) => Questions related to EJS => Topic started by: lookang on August 08, 2012, 05:15:48 pm

 Title: is there an easier way to draw static magnetic field lines of a bar magnet? Post by: lookang on August 08, 2012, 05:15:48 pm dear prof,is there an easier way to draw static magnetic field lines of a bar magnet?notice is my source codes the way i made the visible foe B=1, B=2, B=3, B=4?i cant be doing this way for B=100 for example.is there a way i can use array 3D trails ?or is there a analyticCurve3D for array?thanks! Title: Re: is there an easier way to draw static magnetic field lines of a bar magnet? Post by: Fu-Kwun Hwang on August 08, 2012, 05:35:53 pm I think the way I calculated the field is by using Biot-Savart law.Calculate magnetic field sue to a coil. The solenoid is simple copy of many coils. So just need to sum up the field from one coil.You should be able to calculate it.The magnetic field of a bar is the same as the field of a solenoid. Title: Re: is there an easier way to draw static magnetic field lines of a bar magnet? Post by: lookang on August 08, 2012, 05:43:33 pm i do not mean to use Biot-Savart law which is computational expensive.i am cheating using analyticCurve3Dx = "0.5+0.5*Math.cos(theta)*Math.cos(0)-1*Math.sin(theta)*Math.sin(0)"y = 0z = "0+0.5*Math.sin(theta)*Math.sin(0)-1*Math.sin(theta)*Math.cos(0)"transform "z:270d" etc to get the many lines i need.is there a analyticCurve3D for array? which immediately draws the lines without ODE evolution.thanks!