1.在做“探究凸透镜成像”的实验中:(l)将凸透镜正对太阳光,在透镜的另一侧移动光屏,在距透镜10cm处,屏上呈现出最小最亮的光斑,则此凸透镜焦距约是__________cm。(2)小莉同学做实验时,发现烛焰在光屏上的像偏高,如图1所示,若要使烛焰成像在光屏中心,只调节光屏,应将光屏向__________(填“上”、“下”)调节。图1 1. In doing experiments of “exploring lenticular imaging”: (1) moving the lenticular lens against the sunlight and moving the light screen on the other side of the lens, the lightest and brightest spot on the screen , Then the convex lens focal length is about __________cm. (2) Xiaoli classmates experiment, found that the candle flame on the screen as high, as shown in Figure 1, to make the candle flame imaging at the center of the screen, only adjust the screen, the screen should be _ _________ (fill “on ”, “next ”) adjustment. figure 1