11. which of the following would likely be the best reflector of heat energy?
a. a gritty navy blue surface
b. a bumpy red surface
c. a dull orange surface
d. a polished pale yellow surface

Find an expression for the electric field e⃗ at the center of the semicircle. hint: a small piece of arc length δs spans a small angle δθ=δs /r, where r is the radius. express your answer in terms of the variables q, l, unit vectors i^, j^, and appropriate constants.