In describing Experiment 1, the passage states that a control solution was prepared with no NaCl. Write a paragraph explaining the purpose of a control in an experiment and why this solution functioned as the control for the experiment described in the passage.

Avery long solenoid of inner radius 2.75 cm creates an oscillating magnetic field of the form = for this solenoid, =0.00425 t and =319 rad/s. (a)what is the maximum value of the induced electric field at a perpendicular distance 1.45 cm from the axis of the solenoid? (b) what is the maximum value of the inducted electric field at a point 5.85 cm perpendicular from the axis of the solenoid?