The dolphin would send an underwater message because the water is denser than air and therefore the sound would be louder and would travel faster. The denser the object the faster the sound travels.
Answer:
a = 603.59 m/s^2
Explanation:
from the data given . the rate of change in magnetic field is as follow

from the faraday's law of induction , the expression for the induced emf in region of radius r as follow




electric field at point P_1 as follow



from newton 2nd law of motion, the acceleration of proton is
F = ma
qE = ma


a = 603.59 m/s^2
Number 4 I think
the atomic mass is 11 because the mass is the sum of protons and neutrons