设`A`为` imes n`矩阵，且`(A + E)^2 = O`，则`A^{-1}=` （ ） </p></p>
设`A`为` imes n`矩阵，且`(A + E)^2 = O`，则`A^{-1}=` （ ） </p></p>
设`A`是`m imes n` 矩阵，`x`是`n`维列向量，`b`是`m`维列向量，且`R(A)=r`，则( ) </p></p>
设`A`是`m imes n` 矩阵，`x`是`n`维列向量，`b`是`m`维列向量，且`R(A)=r`，则( ) </p></p>
若一无线电接收机接收到频率为<img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAE4AAAAuCAYAAACGXi9HAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAHDSURBVGhD7Zi9LgVBAIWXFxDRKUTQqCSiEpVCRKWReAPRKryBV/AAtxBCISoUKtEQiR5R6RBegHN2ZmIzdiYidnd27/mSLzN3dleyx/xuJoQQQgghhBBCJMaALdvMOhyC73AMXsFLKCJswxVTzRmB16ZaLYO2bCuL8MNUc16sM/mvCml7cBfwBC7kv74Du7Nlp+Bw2oCxIcV7OAx3bLkP+YwP7+O1T1vyfrZ1Cr7ULuQL3sNYcKeQ9xcpayOc49j+Cvl3J2BnYQih4BgEQ/B7Doche1Zx/nL/DOJ6H5/tbHix4PjyoWsMjkOXMJyygEM9819JcXFYguem+oMbuGaq2agtuYoW4YIxbKrVkVpw7D2xl2ZI7jo3uQ+QG+Ais3DPVKsjteCmbRljErrhuQxXIec5t/r2YGdPDqE5jvsxzmOhOYrP8bo/r9VO2zfAjaHg/khqwT3bMgYXhMZJLbhHW3IBKGMKvkF/C1I7KQ7VAxgKju2HptosKQZ3DOegf2xy393ObNmXxI5cpOzYVMtR6rfU+emce7R5OA432QA4LG+h/7mb+7QtyFPCE+Qz/MZ2BBuf34QQQgghhBBCCCH6nSz7Aq9BTVlX67BIAAAAAElFTkSuQmCC" data-latex="{10}^{8}" />Hz 的电磁波的功率为1微瓦，则每秒接收到的光子数为________<img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAEIAAAArCAYAAADMr156AAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAACySURBVGhD7dbRDYIwFIXhhg2MGziBAzgBEzCZMzgCKxhXcAfjBHBv6Ul4qPgmpvf/khNa6EtPSCEBAAAAAAAghovlZjnm2Wf+/Grp86xBvsGH5VnGNVrjOfmNVm2VEaYEqZURrgRZl+EbD1mCqIypXHcroSvXf3CwvJfh7+1ZhL8N4zJMZ8vLcrfozAihdjCuz4wQZdRKkDBlbJUgIcrQL/a3r4MX4OuGPAMAAAAAoAEpzcx8I76qk+i2AAAAAElFTkSuQmCC" data-latex=" imes "/><img src="data:image/png;base64,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" data-latex="{10}^{19}" />个 A: 1.5 B: 2 C: 1 D: 1.75
若一无线电接收机接收到频率为<img src="data:image/png;base64,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" data-latex="{10}^{8}" />Hz 的电磁波的功率为1微瓦，则每秒接收到的光子数为________<img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAEIAAAArCAYAAADMr156AAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAACySURBVGhD7dbRDYIwFIXhhg2MGziBAzgBEzCZMzgCKxhXcAfjBHBv6Ul4qPgmpvf/khNa6EtPSCEBAAAAAAAghovlZjnm2Wf+/Grp86xBvsGH5VnGNVrjOfmNVm2VEaYEqZURrgRZl+EbD1mCqIypXHcroSvXf3CwvJfh7+1ZhL8N4zJMZ8vLcrfozAihdjCuz4wQZdRKkDBlbJUgIcrQL/a3r4MX4OuGPAMAAAAAoAEpzcx8I76qk+i2AAAAAElFTkSuQmCC" data-latex=" imes "/><img src="data:image/png;base64,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" data-latex="{10}^{19}" />个 A: 1.5 B: 2 C: 1 D: 1.75