15.49 should be the answer if that is 12 watt battery.
Sample:
As soon as the lightning is seen, sound travels in the air for several kilometers until it eventually reaches the observer.
Answer:
option 4
Explanation:
Light's velocity in air ( 3 × 10^8 m/s ) is much greater than sound's velocity in air ( 343 m/s )
Hence due to difference in velocities , during lightning light is seen first & sound is heard later
there were different outcomes each time.
Alkali Metals ......................................