例1 有一个写着F字样的胶片放在教学用投影仪上.此时屏幕上刚好形成一个清晰的像.请在屏幕上画出F的像.如果要得到更大的清晰的像,应使投影仪——(填“远离”或“靠近”)屏幕,并把透镜向——(填“上”或“下”)移动.解析:根据凸透镜成实像的规律:当物体靠近透镜时,所成像远离透镜且实像变大,即“物近像远大”.所以要得到更大清晰的像则应是像 Example 1 There is a film written with F on a teaching projector. At this time, a clear image is formed on the screen. Please draw an image of F on the screen. If you want to get a clearer image, you should To make the projector - (close “away” or “close”) to the screen, and move the lens to - (fill in “” or “down”). Analyze: According to the lenticular lens into a real image Law: When the object approaches the lens, it is imaged away from the lens and the real image becomes large, ie, the object is near imagery. Therefore, to get a clearer image, it should be like