Question

Find the curl of A = (y cos ax)i + (y + e^x)k

(a) 2i – ex j – cos ax k

(b) i – ex j – cos ax k

(c) 2i – ex  j + cos ax k

(d) i – ex j + cos ax k

The question was asked during an internship interview.

Question is from Vector Calculus topic in chapter Vector Calculus of Electromagnetic Theory

Answer 1

Correct answer is (b) i – ex j – cos ax k

The best explanation: Curl A = i(Dy(y + ex)) – j (Dx(y + ex) – Dz(y cos ax)) + k(-Dy(y cos ax))

= 1.i – j(ex) – k cos ax = i – ex j – cos ax k.