question_subject:
Science
question_exam:
NDA-II
stats:
0,11,17,2,5,12,9
keywords:
{'wavelength change': [0, 0, 0, 1], 'glass slab': [0, 0, 0, 1], 'frequency changes': [0, 0, 0, 1], 'frequency': [0, 0, 1, 3], 'velocity change': [0, 0, 0, 1], 'ray': [2, 0, 5, 15], 'light': [16, 4, 34, 62]}