A change that would most improve his results would be; D) Connecting the galvanometer to the coil
Answer:

Explanation:
We have given initial length of the steel guitar l = 1 m
Cross sectional area 
Young's modulus 
Force F = 1500 N
So stress 
We know that young's modulus 
So 

Now strain 


The last one is correct (D)
Answer:
force is a derived quantity
work is a fundamental quantity
2.Force is measured in Newton why work is measured in Newton per seconds (N/s)
Explanation:
no
According to Ohm's law for a portion of the circuit we have:
U=RI=>I=U/R=24/3=8 A
The correct answer is B