# GATE EC 2013

 Question 1
A bulb in a staircase has two switches, one switch being at the ground floor and the other one at the first floor. The bulb can be turned ON and also can be turned OFF by any one of the switches irrespective of the state of the other switch. The logic of switching of the bulb resembles
 A an AND gate B an OR gate C an XOR gate D a NAND gate
Digital Circuits   Logic Gates
Question 1 Explanation:
Truth table of XOR gate
$\begin{array}{cc|c} A & B & Y \\ \hline 0 & 0 & 0 \\ 0 & 1 & 1 \\ 1 & 0 & 1 \\ 1 & 1 & 0 \end{array}$
So, from the XOR gate truth table it is clear that the bulb can be turned ON and also can be turned OFF by any one of the switches irrespective of the state of the other switch.
 Question 2
Consider a vector field ${\overrightarrow{A}}( \overrightarrow{r})$. The closed loop line integral $\int \overrightarrow{A}\cdot \overrightarrow{di}$ can be expressed as
 A $\int \int ( \overline{V}\times \overrightarrow{A} )\cdot \overrightarrow{ds}$ over the closed surface bounded by the loop B $\int \int \int ( \overline{V}\cdot \overrightarrow{A} )dv$ over the closed volume bounded by the loop C $\int \int \int ( \overline{V}\cdot \overrightarrow{A} )dv$ over the open volume bounded by the loop D $\int \int ( \overline{V}\times \overrightarrow{A} )\cdot \overrightarrow{ds}$ over the open surface bounded by the loop
Engineering Mathematics   Calculus
Question 2 Explanation:
According to Stoke's theorem
$\oint_{c} \vec{A} \cdot \vec{d} i=\iint_{s}(\nabla \times \vec{A}) \cdot \overrightarrow{d s}$

 Question 3
Two systems with impulse responses $h_{1}\left ( t \right )$ and $h_{2}\left ( t \right )$ are connected in cascade. Then the overall impulse response of the cascaded system is given by
 A product of $h_{1}\left ( t \right )$ and $h_{2}\left ( t \right )$ B sum of $h_{1}\left ( t \right )$ and $h_{2}\left ( t \right )$ C convolution of $h_{1}\left ( t \right )$ and $h_{2}\left ( t \right )$ D subtraction of $h_{2}\left ( t \right )$ from $h_{1}\left ( t \right )$
Signals and Systems   LTI Systems Continuous and Discrete
Question 3 Explanation:
The overall impulse response h(t) of the cascade system is given by:
$h(t)=h_{1}(t) * h_{2}(t)$
 Question 4
In a forward biased pn junction diode, the sequence of events that best describes the mechanism of current flow is
 A injection, and subsequent diffusion and recombination of minority carriers B injection, and subsequent drift and generation of minority carriers C extraction, and subsequent diffusion and generation of minority carriers D extraction, and subsequent drift and recombination of minority carriers
Electronic Devices   PN-Junction Diodes and Special Diodes
Question 4 Explanation:
In a forward biased pn-junction diode, the current flow is due to diffusion of majority carriers and recombination of minority carriers.
 Question 5
In IC technology, dry oxidation (using dry oxygen) as compared to wet oxidation (using steam or water vapor) produces
 A superior quality oxide with a higher growth rate B inferior quality oxide with a higher growth rate C inferior quality oxide with a lower growth rate D superior quality oxide with a lower growth rate
Electronic Devices   IC Fabrication
Question 5 Explanation:
Dry oxidation has better quality over wet oxidation.
Dry oxidation is slower over wet oxidation.

There are 5 questions to complete.