• # question_answer If the thickness of the plate is 0.5 cm, then quartz plate can't be used to control frequency of A)  $3.62\times {{10}^{4}}\,Hz$         B)  $5.74\times {{10}^{4}}Hz$ C)  $28.7\times {{10}^{4}}Hz$           D)  None of these

For $s=0.5\,\,cm$ ${{f}_{0}}=\frac{2.87\times {{10}^{4}}}{0.5}=5.74\times {{10}^{4}}\,Hz$ So, the plate can vibrate with frequencies ${{f}_{0}},\,\,2{{f}_{0}},...,$ only.