2) black body(黑体) black-body radiation(黑体辐射) 抛光的铜镜表面吸收率:=0.02 般金属表面吸收率:a=06-08 煤烟吸收率: =0.95-0.98 Let us construct cavity in a metal block, through the wall of which a small hole is drilled. this small hole is called a black body.(as=1) 如远处不点灯的窗翻 若室内点灯 (是自身辐射)2）black body (黑体) black-body radiation (黑体辐射) 抛光的铜镜表面吸收率： 一般金属表面吸收率： 煤烟吸收率： a 总 = 0.02 a 总 = 0.6−0.8 a 总 = 0.95−0.98 Let us construct cavity in a metal block, through the wall of which a small hole is drilled. This small hole is called a black body. (a总=1) 如远处不点灯的窗 若室内点灯 （是自身辐射）