As per Kepler's third law we know that

now here we know that
= year of Neptune
= year of Earth
= distance of Neptune from Sun
= Distance of Earth from Sun
so now we will have



so length of year of Neptune is 164.3 years
Answer:
<h2>
16,931 turns</h2>
Explanation:
The magnetic field produced is expressed using the formula

B is the magnetic field = 0.30T
I is the current produced in the coil = 4.5A
is the magnetic permittivity in vacuum = 1.26*10^-6Tm/A
L is the length of the solenoid = 32 cm = 0.32 m
N is the number of turns in the solenoid.
Making N the subject of the formula from the equation above;


Substituting the give values to get N;

The number of turns the solenoid must have is approximately 16,931 turns