A 1.75-kg picture frame is hung on the wall by means of a horizontal string on the back of the frame. The string is attached to screws on the sides of the frame, which are separated by a distance of 37.0 cm. When hung from a nail on the wall, the string is
displaced at its center by a vertical distance of 4.00 cm. What is the tension T in the string?

where is the photo and the answer choices?

answer///isobars;

the answer is the first electromagnet (a). this is because it has more coils around the ferromagnetic material. increasing the number of coils increases the surface area in which the metal interacts with the current in the coil. this enables more atoms in the metal to become aligned hence becoming more magnetized.