light
Light light torches before heavy ones in emergencies.
The sentence advises igniting the lighter-weight torches before the heavier ones during emergencies.

Meanings (pronounced /laɪt/)
to ignite or set fire to; to provide illumination
- Light the candles before the guests arrive.
- She lit the fire with a single match.
of small weight; not heavy
- Carry-on bags must be light enough to lift overhead.
- She prefers light fabrics for summer.
Word origin
Two etymologically distinct words that converged: 'light' the verb /laɪt/ ('to ignite, set fire to') is from Old English līhtan, from Proto-Germanic *liuhtijaną, related to 'lightning' and 'illuminate.' 'Light' the adjective /laɪt/ ('not heavy') is from Old English lēoht, from a different Proto-Germanic root *linhtaz meaning 'small in weight.' The two converged in Middle English by accident.
Fun fact
The two 'lights' (illumination/weight) come from two different Proto-Germanic roots, but English speakers see them as a single word with multiple meanings. The 'fire/illumination' sense was *liuhtijaną, related to 'lightning' and 'bright.' The 'low weight' sense was *linhtaz. They converged through similar pronunciation and spelling — a coincidence that English-as-a-second-language learners regularly find confusing.