1. Department of Physics, R. S. More College, Vinoba Bhave University, Hazaribag, Govindpur 828109, India
2. Department of Physics, Sindri College, Vinoba Bhave University, Hazaribag, Sindri 828122, India
3. Department of Physics, P. K. R. M. College, Vinoba Bhave University, Hazaribag, Dhanbad 826004, India