Magnetic resonance imaging needs a magnetic field strength of 1.5 T. The solenoid is 1.8 m long and 75 cm in diameter. It is tightly wound with a single layer of 2.20-mm-diameter superconducting wire. Required:
What current is needed?

The current needed is 2625.72 A.

Explanation:

Given;

magnetic field strength, B = 1.5 T

length of the solenoid, L = 1.8 m

diameter of the solenoid, d = 75 cm

The number of turns is given by;

The magnetic field is given by;

where;

I is the current needed

Therefore, the current needed is 2625.72 A.

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

the answer is to check all of them! they all apply well at least i think so!