Which of the following is an example of an electromagnetic wave?
a. ripples on a lake
b. the honking of a car horn
c. the light from a neon sign
d. aftershocks from an earthquake

The first-order reaction a→2b+c has rate constant 0.538 s−1. if the initial concentration of a is 0.867 mol l−1, what is the half-life of the reaction in seconds? remember to use correct significant figures in your answer (round your answer to the nearest hundredth). do not include units in your response.