Answer:
I think they use it at night because they want to avoid involving themselves in road accident while crossing the street. When there are reflective strips on their clothes, drivers do notice them even at far ends of the street since the strips will reflect the rays from the car lights to the driver,hence, the driver notifies that there is a pedestrian crossing and therefore slows down.
Answer:
Frequency required will be 2421.127 kHz
Explanation:
We have given inductance 
Current in the inductor 
Voltage v = 13 volt
Inductive reactance of the circuit 

We know that


f = 2421.127 kHz
Answer:à
Explanation:waves carry energy in the direction in which they move
The answer is allotropes. Hope this helps. Have a great day.