JEE Main Question Paper 2020 (Available): Check Previous Year Question Paper with Solution PDF (2024-2014)

JEE Main 2020 Questions

• 1.

  A Wheatstone bridge is initially at room temperature and all arms of the bridge have same value of resistances \[ (R_1=R_2=R_3=R_4). \] When \(R_3\) resistance is heated, its resistance value increases by \(10%\). The potential difference \((V_a-V_b)\) after \(R_3\) is heated is _______ V.

  • \(0\)
    
  • \(0.95\)
    
  • \(2\)
    
  • \(1.05\)
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• 2.

  Let
  \[ A=\begin{pmatrix} 3 & -4 \\ 1 & -1 \end{pmatrix} \] and \( B \) be two matrices such that
  \[ A^{100}-100B+I=0. \]
  Then the sum of all the elements of \( B^{100} \) is _______.
  

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• 3.

  Net gravitational force at the center of a square is found to be \( F_1 \) when four particles having masses \( M, 2M, 3M \) and \( 4M \) are placed at the four corners of the square as shown in figure, and it is \( F_2 \) when the positions of \( 3M \) and \( 4M \) are interchanged. The ratio \( \dfrac{F_1}{F_2} = \dfrac{\alpha}{\sqrt{5}} \). The value of \( \alpha \) is 
  

  • 1
    
  • 3
    
  • \( 2\sqrt{5} \)
    
  • 2
    
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• 4.

  If the distances of the point \( (1,2,a) \) from the line \[ \frac{x-1}{1}=\frac{y}{2}=\frac{z-1}{1} \] along the lines \[ L_1:\ \frac{x-1}{3}=\frac{y-2}{4}=\frac{z-a}{b} \quad \text{and} \quad L_2:\ \frac{x-1}{1}=\frac{y-2}{4}=\frac{z-a}{c} \] are equal, then \( a+b+c \) is equal to:

  • \(5\)
  • \(6\)
  • \(4\)
  • \(7\)
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• 5.

  The magnetic field at the centre of a current carrying circular loop of radius \(R\) is \(16\,\mu\text{T}\). The magnetic field at a distance \(x=\sqrt{3}R\) on its axis from the centre is ____ \(\mu\text{T}\).

  • 4

  • 8

  • \(2\sqrt{2}\) 

  • 2

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