The interchange factor for radiation heat transfer from surface 'x' to surface 'y' in case of an infinite parallel planes with emis-sivities $${\varepsilon _{\text{x}}}$$ & $${\varepsilon _{\text{y}}}$$ is given by

Consider the 5 × 5 matrix \[{\text{A}} = \left[ {\begin{array}{*{20}{c}} 1&2&3&4&5 \\ 5&1&2&3&4 \\ 4&5&1&2&3 \\ 3&4&5&1&2 \\ 2&3&4&5&1 \end{array}} \right

A

\

B

It is given that A has only one real eigen value.
Then the real eigen value of A is

C

A. -2.5

D

0

For infinite parallel planes having emis-sivities $${{\varepsilon _1}}$$ & $${{\varepsilon _2}}$$, the interchange factor for radiation from surface 1 to surface 2 is given by

A

$$\frac{{{\varepsilon _1} + {\varepsilon _2}}}{{{\varepsilon _1}.{\varepsilon _2}}}$$

B

$$\frac{{{\varepsilon _1}.{\varepsilon _2}}}{{{\varepsilon _1} + {\varepsilon _2} - {\varepsilon _1}.{\varepsilon _2}}}$$

C

$${\varepsilon _1}.{\varepsilon _2}$$

D

$${\varepsilon _1} + {\varepsilon _2}$$

Select from the alternatives that combination of numbers, which will form a meaningful word if given letters are arranged accordingly. $\begin{matrix} \ \ \ \text{A} & \rm R & \rm W & \rm L & \rm E & \rm K \\\ \downarrow & \downarrow & \downarrow & \downarrow & \downarrow & \downarrow \\\ \ \ 1 & 2 & 3 & 4 & 5 & 6 \end{matrix}$

A

314652

B

413652

C

251462

D

652314

An infinite parallel planes with emissivities e₁ and e₂, the interchange factor for radiation from surface 1 to surface 2 is given by

A

$$\frac{{{{\text{e}}_1}{{\text{e}}_2}}}{{{{\text{e}}_1} + {{\text{e}}_2} - {{\text{e}}_1}{{\text{e}}_2}}}$$

B

$$\frac{1}{{{{\text{e}}_1}}} + \frac{1}{{{{\text{e}}_2}}}$$

C

e₁ + e₂

D

e₁e₂

Consider radiative heat transfer between two large parallel planes of surface emissivities 0.8. How many thin radiation shields of emissivity 0.05 be placed between the surfaces is to reduce the radiation heat transfer by a factor of 75?

A

1

B

2

C

3

D

4

The interchange factor for radiation heat transfer from surface 'x' to surface 'y' in case of an infinite parallel planes with emis-sivities εx & εy is given by

A

Εx + εy

B

Εx . εy

C

1/εx + 1/εy

D

(εx + εy)/(εx + εy - εx . εy)

Let A be an m × n matrix and Ban n × m matrix. It is given that determinant ($$I$$_m + AB) = determinant ($$I$$_n + BA), where $$I$$_k is the k × k identity matrix. Using the above property, the determinant of the matrix given below is
\[\left[ {\begin{array}{*{20}{c}} 2&1&1&1 \\ 1&2&1&1 \\ 1&1&2&1 \\ 1&1&1&2 \end{array}} \right

A

\

B

A. 2

C

5

At the interface between two linear dielectrics (with dielectric constants $${{\varepsilon _1}}$$ and $${{\varepsilon _2}}$$), the electric field lines bend, as shown in the figure. Assume that there are no free charges at the interface. The ratio $$\frac{{{\varepsilon _1}}}{{{\varepsilon _2}}}$$ is
Electromagnetic Theory mcq question image

Electromagnetic Theory mcq question image

A

$$\frac{{\tan {\theta _1}}}{{\tan {\theta _2}}}$$

B

$$\frac{{\cos {\theta _1}}}{{\cos {\theta _2}}}$$

C

$$\frac{{\sin {\theta _1}}}{{\sin {\theta _2}}}$$

D

$$\frac{{\cot {\theta _1}}}{{\cot {\theta _2}}}$$

Eigen values of the matrix \[\left[ {\begin{array}{*{20}{c}} 0&1&0&0 \\ 1&0&0&0 \\ 0&0&0&{ - 2i} \\ 0&0&{2i}&0 \end{array}} \right

A

\

B

are

C

A. -2, -1, 1, 2

D

-1, 1, 0, 2

In a coded language “ADETP” is coded as “$&$&&” and “DTPQUV” is coded as “&&&&$&”? What is the code word for “&&$$&$”?

A

GHDEIP

B

GHEUKO

C

IJKLMO

D

KLOAEU

The interchange factor for radiation heat transfer from surface 'x' to surface 'y' in case of an infinite parallel planes with emis-sivities $${\varepsilon _{\text{x}}}$$ & $${\varepsilon _{\text{y}}}$$ is given by

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