Authors
M. Sirait
Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Medan, Medan, Indonesia
K.Sari Dewi Saragih
Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Medan, Medan, Indonesia
Nurfajriani
Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Negeri Medan, Medan, Indonesia
S. Gea
Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of North Sumatra, Medan, Indonesia