[填空题]
The first-order line of 589-nm light falling on a diffraeu;;1hwerm .zf 6 lvg1ction grating ;b7y z- y3 81t dslsp6z;r4dayz4 qmssis observed at a 15.q41 bsy;s r63 8ddzmlpz 7-sats4y;yz5$^{\circ}\,$ angle. How far apart are the slits? $\mu m$
At what angle will the third order be observed?
