The area under which of these graphs can be used to estimate the value of impulse?

Graph A

Explanation:

The impulse of a force F is defined as the integral of the force F over the time, t:

where t1 and t2 represent the time interval during which the force F is applied.

If we compare this to the graph, we see that the impulse J basically corresponds to the area under the graph of the force, F, against the time, t. So, in this case, it corresponds to choice A, which represents exactly this graph (force against time).

adding a(n) to an electric circuit would increase the magnetic field around a wire;

b. solenoid

a solenoid is a type of electromagnet whose purpose is to generate a controlled magnetic field.

if the purpose of the solenoid is instead to impede changes in the electric current, a solenoid can be more specifically classified as an inductor rather than an electromagnet.