# GATE EE 2009

 Question 1
The pressure coil of a dynamometer type wattmeter is
 A Highly inductive B Highly resistive C Purely resistive D Purely inductive
Electrical and Electronic Measurements   Measurement of Energy and Power
Question 1 Explanation:
It is difficult to have purely resistive pressure coil. The pressure coil has a small value of inductance, due to which error occurs in wattmeter readings.
 Question 2
The measurement system shown in the figure uses three sub-systems in cascade whose gains are specified as $G_1,G_2 \; and \; \frac{1}{G_3}$. The relative small errors associated with each respective subsystem $G_1,G_2 \; and \; G_3$ are $\varepsilon _1,\varepsilon _2 \; and \; \varepsilon _3$. The error associated with the output is : A $\varepsilon _{1}+ \varepsilon _{2} +1/ \varepsilon _{3}$ B $\frac{\varepsilon _{1}\varepsilon _{2}} {\varepsilon _{3}}$ C $\varepsilon _{1}+ \varepsilon _{2} -\varepsilon _{3}$ D $\varepsilon _{1}+ \varepsilon _{2} +\varepsilon _{3}$
Electrical and Electronic Measurements   Characteristics of Instruments and Measurement Systems
Question 2 Explanation:
$\frac{dG_1}{G_1}=\varepsilon _1,$ $\frac{dG_2}{G_2}=\varepsilon _2,$and $\frac{dG_3}{G_3}=\varepsilon _3$
Output $(y)_0=\frac{G_1G_3}{G_3}x$
where, $\;\; x=input$
$\ln y=\ln G_1+ \ln G_2- \ln G_3 +\ln x$
Differentiating both side,
$\frac{dy}{y}=\frac{dG_1}{G_1}+\frac{dG_2}{G_2}-\frac{dG_3}{G_3}+\frac{dx}{x}$
No error is specified in input, so $\frac{dx}{x}=0$
$\frac{dy}{y}==\varepsilon _1+\varepsilon _2-\varepsilon _3$

 Question 3
The following circuit has a source voltage $V_s$ as shown in the graph. The current through the circuit is also shown. The element connected between a and b could be A A B B C C D D
Analog Electronics   Miscellaneous
Question 3 Explanation:
Diode act as a switch. When forward biased it is short circuited. But when suddenly reverse biased, current does not become zero instantly , initially the same current flow in opposite direction and after some time (turn off time) it will become zero.
 Question 4
The two inputs of a CRO are fed with two stationary periodic signals. In the X-Y mode, the screen shows a figure which changes from ellipse to circle and back to ellipse with its major axis changing orientation slowly and repeatedly. The following inference can be made from this.
 A The signals are not sinusoidal B The amplitudes of the signals are very close but not equal C The signals are sinusoidal with their frequencies very close but not equal D There is a constant but small phase difference between the signals
Electrical and Electronic Measurements   CRO and Electronic Measurements
Question 4 Explanation: Because phase difference only patterns changes from ellipse to circle and back to ellipse.
 Question 5
The increasing order of speed of data access for the following device is

(I) Cache Memory
(II) CD-ROM
(III) Dynamic RAM
(IV) Processor Registers
(V) Magnetic Tape
 A (V), (II), (III), (IV), (I) B (V), (II), (III), (I), (IV) C (II), (I), (III), (IV), (V) D (V), (II), (I), (III), (IV)
Digital Electronics   Microprocessors
Question 5 Explanation:
Access time of the residter is very less than that from a memory access. So speed of data access is faster in case of processor register.
Second highest is cache memory because it's size is small, so searching of data takes less time.

There are 5 questions to complete.