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BITSAT2021PhysicsCurrent ElectricityActual

A wire of a certain material is stretched slowly by ten per cent. Its new resistance and specific resistance become respectively:

Options

  1. A1.2 times, 1.3 times
  2. B1.21 times, same
  3. Cboth remain the same
  4. D1.1 times, 1.1 times

Correct answer

B. 1.21 times, same

Step-by-step solution

( R = l A ) Now, (1=1+ 1 10 = 111 10 ) and therefore, ( A = 10 ~A 11 ) So ( R ^ = p ( 111 10 ) 10 ~A 11 = l A (11)² (10)² =1.21 R ) Now resistance becomes (1.21 ) times of initial and specific resistance is the intrinsic property so remains same.

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