Is a property that determines how much current will flow for a given source voltage, whereas a is a device that controls the current in a circuit

“RESISTANCE” is a property that determines how much current will flow for a given source voltage, whereas a “RESISTOR” is a device that controls the current in a circuit.

The property which determines the amount of current to be flown for a given source voltage is the Resistance and the device which controls it is the Resistor.

Explanation:

The resistance is the property of an electric circuit which can resist the flow of current across the circuit. Similarly, to keep in check the current of an electric circuit, resistor is used as a device, which has a predetermined or preset amount of electrical resistance. The resistance unit is ohm.  

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.