Does a perfectly elastic body exit in nature ?

What is a perfectly plastic body ?

What is young's modulus of perfectly elastic body ?

What is perfectly elastic collision ?

Calculate temperature at perfectly black body radiates energy at the rate 5.67 xx 10^4 W/m^2 .

On applying a stress of 20 xx 10^8 N/m^2 , the length of a perfectly elastic wire is doubled. Its Young's modulus will be

The absorptive power of a perfectly black body is_____.