<span>
The taut guitar string haspotencial energy which we can see in action.</span> <span>· so option a is correct.</span>
Answer:
b. 
Explanation:
As we know that the electric field due to infinite line charge is given as

here we can find potential difference between two points using the relation

now we have

now we have

now plug in all values in it


now we know by energy conservation


Answer:
Current in the toroid will be 
Explanation:
We have given number of winding in rectangular toroid N = 1500
Self inductance of toroid L = 0.06 H
Magnetic energy stored in toroid 
We have to find the current in the toroid
Magnetic energy stored is equal to 


So current in the toroid will be 
Divide the distance traveled by the time it took:
(100 m) / (4.2 s) ≈ 23.8 m/s