The frequency of oscillation of a torsional pendulum is
A. $$\frac{{2\pi {\text{k}}}}{{\text{r}}}\sqrt {\frac{{\text{g}}}{l}} $$
B. $$\frac{{\text{r}}}{{2\pi {\text{k}}}}\sqrt {\frac{l}{{\text{g}}}} $$
C. $$\frac{{2\pi {\text{r}}}}{{\text{k}}}\sqrt {\frac{{\text{g}}}{l}} $$
D. $$\frac{{\text{r}}}{{2\pi {\text{k}}}}\sqrt {\frac{{\text{g}}}{l}} $$
Answer: Option D

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