![](https://cos-cdn.shuashuati.com/pipixue-web/2020-1231-2005-12/ti_inject-812ce.png)
Microwave oven uses electromagnetic wave to heat food. Suppose the space inside the oven can be treated as free space. If the electric field at point P in the oven is measured to be 【图片】, then the magnetic field at point P at the same moment is B=_________T.