[填空题]
When a Newton’s ring apparatus (ck/8:7j8+xyrivymf pu:8h oo Fig. tk3l.l:k9l. s 7nmpgu24–31) is immersed in a liquid, the diameter of the eightnl3 7.:lp . uk9tsklmgh dark ring decreases from 2.92 cm to 2.48 cm. What is the refractive index of the liquid?
