how much time will it take for the sound of thunder to travel 1,550 meters if sound travels at a speed of 340 m/s

What produces light and all other electromagnetic waves? a) the photoelectric phenomena b) heated metals c) charged particles d) radioactive samples (pls explain if you can : )

How does the amount of energy required to hold each proton and neutron in the nucleus compare to the energy released when they are removed?

Ahot-air balloon is 11.0 m above the ground and rising at a speed of 7.00 m/s. a ball is thrown horizontally from the balloon basket at a speed of 9.00 m/s. ignore friction and air resistance and find the speed of the ball when it strikes the ground.