If the strength of the magnetic field at a is 10 units, the strength of the magnetic field at b is 640 units 6.4 units 2.5 units 1.25 units next

Answer : Option C) 2.5 units

Explanation : For calculating the strength of a unknown magnetic field in comparison with the given magnetic field we can use the magnetic formula as;



On substituting the values we get; 

 ;

On solving we get the magnetic B field strength as 2.5 units

I’d have to say no because without oxygen in the water the fish would all be dead. so if you want to fish for dead fish, pick the ponds with the lowest oxygen concentrations.

D.na is the answer hope this