its D. B and D beacuse tthat the neap tides
Answer:
option(d)
Explanation:
The frequency of a wave is the property of the source of wave.
The velocity of all the electromagnetic waves is same as the speed of light. It only changes as the light passes through one medium to another.
The frequency is defined as the number of waves coming out from the source in 1 second.
As the frequency of wave increases, the number of wave coming per second increases.
So, the number of waves passing by increases but the speed remains same.
Option (d)
Answer:
The force per unit length is 
Explanation:
The current carrying by each wires = 2.85 A
The current in both wires flows in same direction.
The gap between the wires = 6.10 cm
Now we will use the below expression for the force per unit length. Moreover, before using the below formula we have to change the unit centimetre into meter. So, we just divide the centimetre with 100.

C. A mechanical wave generally travels faster in gases than liquids.