Can someone taking Engineering and Design help me answer this Quizlet?

The y form of iron is known as: a) ferrite b) cementite c) perlite d) austenite

Thermal stresses are developed in a metal when its a) initial temperature is changed b) final temperature is changed c) density is changed d) thermal deformation is prevented e) expansion is prevented f) contraction is prevented

The filament of an incandescent lamp has a temperature of 2000k. calculate the fraction of radiation emitted in the visible light band if the filament is approximated as blackbody