Electromagnetic Theory Questions and Answers – Gradient

This set of Electromagnetic Theory Multiple Choice Questions & Answers (MCQs) focuses on “Gradient”.

1. Gradient of a function is a constant. State True/False.
a) True
b) False
View Answer

Answer: b
Explanation: Gradient of any scalar function may be defined as a vector. The vector’s magnitude and direction are those of the maximum space rate of change of φ.

2. The mathematical perception of the gradient is said to be
a) Tangent
b) Chord
c) Slope
d) Arc
View Answer

Answer: c
Explanation: The gradient is the rate of change of space of flux in electromagnetics. This is analogous to the slope in mathematics.

3. Divergence of gradient of a vector function is equivalent to
a) Laplacian operation
b) Curl operation
c) Double gradient operation
d) Null vector
View Answer

Answer: a
Explanation: Div (Grad V) = (Del)2V, which is the Laplacian operation. A function is said to be harmonic in nature, when its Laplacian tends to zero.
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4. The gradient of xi + yj + zk is
a) 0
b) 1
c) 2
d) 3
View Answer

Answer: d
Explanation: Grad (xi + yj + zk) = 1 + 1 + 1 = 3. In other words, the gradient of any position vector is 3.

5. Find the gradient of t = x2y+ ez at the point p(1,5,-2)
a) i + 10j + 0.135k
b) 10i + j + 0.135k
c) i + 0.135j + 10k
d) 10i + 0.135j + k
View Answer

Answer: b
Explanation: Grad(t) = 2xy i + x2 j + ez k. On substituting p(1,5,-2), we get 10i + j + 0.135k.

6. Curl of gradient of a vector is
a) Unity
b) Zero
c) Null vector
d) Depends on the constants of the vector
View Answer

Answer: c
Explanation: 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).

7. Find the gradient of the function given by, x2 + y2 + z2 at (1,1,1)
a) i + j + k
b) 2i + 2j + 2k
c) 2xi + 2yj + 2zk
d) 4xi + 2yj + 4zk
View Answer

Answer: b
Explanation: Grad(x2+y2+z2) = 2xi + 2yj + 2zk. Put x=1, y=1, z=1, the gradient will be 2i + 2j + 2k.
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8. The gradient can be replaced by which of the following?
a) Maxwell equation
b) Volume integral
c) Differential equation
d) Surface integral
View Answer

Answer: c
Explanation: Since gradient is the maximum space rate of change of flux, it can be replaced by differential equations.

9. When gradient of a function is zero, the function lies parallel to the x-axis. State True/False.
a) True
b) False
View Answer

Answer: a
Explanation: Gradient of a function is zero implies slope is zero. When slope is zero, the function will be parallel to x-axis or y value is constant.
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10. Find the gradient of the function sin x + cos y.
a) cos x i – sin y j
b) cos x i + sin y j
c) sin x i – cos y j
d) sin x i + cos y j
View Answer

Answer: a
Explanation: Grad (sin x + cos y) gives partial differentiation of sin x+ cos y with respect to x and partial differentiation of sin x + cos y with respect to y and similarly with respect to z. This gives cos x i – sin y j + 0 k = cos x i – sin y j.

Sanfoundry Global Education & Learning Series – Electromagnetic Theory.
To practice all areas of Electromagnetic Theory, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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