Consider a source which emits radiation of 500 nm wavelength. the linewidth of the emitted radiation is 1 nm. the coherence length | l c | is : (a) 2·5

Consider a source which emits radiation of 500 nm wavelength. The linewidth of the emitted radiation is 1 nm. The coherence length | l c | is : (A) 2·5 m (B) 250 m (C) 1·0 m (D) 100 m