For each example, identify the reading condition before giving the reason for heavy or light ra:
«رِجَالٌ» — vowelled ra with kasrah: light.
«بَرْقٌ» — still ra after fathah: heavy.
«فِرْعَوْنَ» — still ra after original kasrah: light.
«قِرْطَاسٍ» — still ra after kasrah but before ط in the same word: heavy.
«خَيْرٌ» at a pause — still ya before ra: light.
«الْقَدْرِ» at an ordinary pause — still ra follows still dal; earlier qaf has fathah: heavy.
When two cases seem alike, check whether the earlier vowel is original, what follows ra, word boundaries and pausing conditions.