1. Department of Physics, Moulana Azad College, 8, Rafi Ahmed Kidwai Road, Kolkata 700013, India
2. Physics and Applied Mathematics Unit (PAMU), Indian Statistical Institute, Kolkata 700108, India
3. Beramara Ramchandrapur High School, South 24-Pgs, 743609(WB), India
4. West Kodalia Adarsha Siksha Sadan, New Barrackpore, Kolkata-700131, India