Answer:
A real emf device has an internal resistance, but an ideal emf device does not.
Answer:
Explanation:
The wires are in circular shape . They have common center .
magnetic field due to circular wire is given by the formula
B = 
where I is current , r is radius of the coil .
magnetic field due to inner wire
= 
magnetic field due to outer wire
= 
These should be equal and opposite so that by cancelling each other , they create zero field.
= 
I = 16.66 A
Direction of current should be in opposite direction ie anticlockwise when looking from above.
Generally, the length of the line will indicate how strong the force is. If you have two opposing forces and one is higher than the other, you would draw the line of the higher force visibly longer.