Question

Curl of gradient of a vector is

(a) Unity

(b) Zero

(c) Null vector

(d) Depends on the constants of the vector

The question was asked in a national level competition.

My doubt is from Gradient topic in chapter Vector Calculus of Electromagnetic Theory

Answer 1

The correct answer is (c) Null vector

To explain I would say: Gradient of any function leads to a vector. Similarly curl of that vector gives another vector, which is always zero for all constants of the vector. A zero value in vector is always termed as null vector(not simply a zero).