1. Department of Physics, Collage of Natural and Computational Sciences, Wolaita Sodo University, P.O. Box 318, Wolaita Sodo, Ethiopia
2. Center for Environmental Science, College of Natural and Computational Sciences, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia
3. Department of Educational Planning and Management, Collage Education and Behavioral Sciences, Wolaita Sodo University, P.O. Box 318, Wolaita Sodo, Ethiopia
4. Department of Physics, Collage of Natural and Computational Sciences, Wollo University, P.O. Box 1145, Dessie, Ethiopia
5. Department of Physics, College of Natural and Computational Sciences, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia
6. Department of Natural Resource Management, Wolkite University, P. O. Box 07, Wolkite, Ethiopia