A light detector is located at the centre of a train carriage, if the light detector receives light pulses simultaneously from two lamps at either end of the carriage an alarm will sound. At time t=100ns on a clock in the carriage the alarm sounds. 1)What time did the left and right lamps each emit a light pulse according to the clock on the carriage. 2)An observer is outside the carriage, while the carriage travels past at v=0.99c. The observers records that the bell rings at 200ns past 12pm. At what time did the lamps switch on according to the outside observer. (You may neglect the transit time of light or sound to the outside observer).

A light detector is located at the centre of a train carriage, if the light detector receives light pulses simultaneously from two lamps at either end of the carriage an alarm will sound. At time t=100ns on a clock in the carriage the alarm sounds. 1)What time did the left and right lamps each emit a light pulse according to the clock on the carriage. 2)An observer is outside the carriage, while the carriage travels past at v=0.99c. The observers records that the bell rings at 200ns past 12pm. At what time did the lamps switch on according to the outside observer. (You may neglect the transit time of light or sound to the outside observer).