JEE Main PYQs on Error Analysis: JEE Main Questions for Practice with Solutions

JEE Main Questions

• 1.

  Consider a long thin conducting wire carrying a uniform current \( I \). A particle having mass \( M \) and charge \( q \) is released at a distance \( a \) from the wire with a speed \( v_0 \) along the direction of current in the wire. The particle gets attracted to the wire due to magnetic force. The particle turns round when it is at distance \( x \) from the wire. The value of \( x \) is:

  • \( \frac{a}{2} \)
    
  • \( a \left( 1 - \frac{mv_0}{q\mu_0 I} \right) \)
    
  • \( ae \left( -4 \frac{mv_0}{q\mu_0 I} \right) \)
    
  • \( a \left[ 1 - \frac{mv_0}{2q\mu_0 I} \right] \)
    
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• 2.

  A force \( \vec{f} = x^2 \hat{i} + y \hat{j} + y^2 \hat{k} \) acts on a particle in a plane \( x + y = 10 \). The work done by this force during a displacement from \( (0,0) \) to \( (4m, 2m) \) is              Joules (round off to the nearest integer).

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• 3.

  Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). 
  Assertion (A) : If Young’s double slit experiment is performed in an optically denser medium than air, then the consecutive fringes come closer. 
  Reason (R) : The speed of light reduces in an optically denser medium than air while its frequency does not change. 
  In the light of the above statements, choose the most appropriate answer from the options given below :

  • Both (A) and (R) are true and (R) is the correct explanation of (A)
    
  • (A) is false but (R) is true.
    
  • Both (A) and (R) are true but (R) is not the correct explanation of (A)
    
  • (A) is true but (R) is false.
    
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• 4.

  The maximum speed of a boat in still water is 27 km/h. Now this boat is moving downstream in a river flowing at 9 km/h. A man in the boat throws a ball vertically upwards with speed of 10 m/s. Range of the ball as observed by an observer at rest on the river bank is cm. (Take g = 10 m/s²).

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• 5.

  A bar magnet has total length \( 2l = 20 \) units and the field point \( P \) is at a distance \( d = 10 \) units from the centre of the magnet. If the relative uncertainty of length measurement is 1%, then the uncertainty of the magnetic field at point P is:
  

  

  • 10%
    
  • 4%
    
  • 5%
    
  • 3%
    
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• 6.

  The ratio of the power of a light source \( S_1 \) to that of the light source \( S_2 \) is 2. \( S_1 \) is emitting \( 2 \times 10^{15} \) photons per second at 600 nm. If the wavelength of the source \( S_2 \) is 300 nm, then the number of photons per second emitted by \( S_2 \) is \_\_\_\_\_ \( \times 10^{14} \).

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