What did nikola tesla spend his time/money doing?

If you touch a hot light bulb and get burned, that is an example of a. radiation b. convection c. conduction

The rigid beam is supported by the three suspender bars. bars ab and ef are made of aluminum and bar cd is made of steel. if each bar has a cross-sectional area of 450 mm2, determine the maximum value of p if the allowable stress is (σallow)st = 200 mpa for the steel and ( σallow)al = 150 mpa for the aluminum. est = 200 gpa and eal = 70 gpa.

Ineed the answer to question 1 , i’m desperate