Tomato plant fungus or deficiency?

by Cathy
(Pennsylvania)

My daughter is growing cherry tomatoes indoors with magnets for a science fair experiment. Most of the plants have leaves that are turning yellow and have brown spots.

Her teacher said it was a deficiency, but we used miracle grow soil. wondering if it is a fungus. I would appreciate any insight as to how to save these plants. Also, we are using a 1000 watt high pressure sodium light that's is on for 16 1/2 hrs each day and temp in the room averages 82 degrees.

Thanks