[单项选择]What is probably the real reason for Mr. Smith not feeling well A. He was preoccupied with his business. B. He ate too much rich food. C. He couldn’t sleep well. D. He was overweight.
第1题: [单项选择]关于X线的叙述,错误的是()。 A. X线比可见光的波长短 B. X线本质是一种电磁波 C. X线具有一定的波长和频率 D. X线属于电磁波中的电离辐射 E. X线是带电粒子 参考答案:E 答案解析:X线本质是一种电磁波,具有一定的波长和频率,由于X线光子能量大,可使物质产电离,故属于电磁波中的电离辐射,X线肉眼看不见,不带电。