GATE 1997 Electronics and Communication Engineering (EC) Question Paper with Answer Key PDF

GATE Questions

• 1.

  During a welding operation, thermal power of 2500 W is incident normally on a metallic surface. As shown in the figure below (figure is NOT to scale), the heated area is circular. Out of the incident power, 85% of the power is absorbed within a circle of radius 5 mm while 65% is absorbed within an inner concentric circle of radius 3 mm. The power density in the shaded area is _________ W mm^-2 (rounded off to 2 decimal places).

  

  
   

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• 2.

  For the differential equation given below, which one of the following options is correct? \[ \frac{\partial^2 u}{\partial x^2} + \frac{\partial^2 u}{\partial y^2} = 0, \quad 0 \leq x \leq 1, 0 \leq y \leq 1 \]

  • \( u = e^{x + y} \) is a solution for all \(x\) and \(y\)
    
  • \( u = e^{x} \sin y \) is a solution for all \(x\) and \(y\)
    
  • \( u = \sin x \sin y \) is a solution for all \(x\) and \(y\)
    
  • \( u = \cos x \cos y \) is a solution for all \(x\) and \(y\)
    
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• 3.

  Let A and B be real symmetric matrices of same size. Which one of the following options is correct?

  • \( (AB)^T = B^T A^T \)
    
  • \( AB = BA \)
    
  • \( A^T = A^{-1} \)
    
  • \( A = A^{-1} \)
    
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• 4.

  A truss structure is loaded as shown in the figure below. Among the options given, which member in the truss is a zero-force member?

  

  \[ {Given: } F = 1000\,{N} \]

  • \(BD\)
    
  • \(BC\)
    
  • \(BA\)
    
  • \(AD\)
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• 5.

  The state of stress at a point is shown in the figure given below. Under plane stress assumption, the normal strain along the thickness direction (\(\epsilon_{zz}\)) is _________ (rounded off to 2 decimal places).

  

  
   

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• 6.

  The values of a function \( f \) obtained for different values of \( x \) are shown in the table below.

  

  Using Simpson’s one-third rule, approximate the integral \[ \int_0^1 f(x) \, dx \quad \text{(rounded off to 2 decimal places)}. \]

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