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NEET-XI-Physics

exam-1 year:2016

with Solutions - page 3
Qstn# 40 Prvs-QstnNext-Qstn
  • #40
    An inductor 20 mH, a capacitor 50 µF and a resistor
    40 ``\Omega`` are connected in series across a source of emf
    V = 10 sin 340 t. The power loss in A.C. circuit is :-
    (1) 0.51 W
    (2) 0.67 W
    (3) 0.76 W
    (4) 0.89 W
    digAnsr:   1
    Ans : 1
    Sol. XC = =   -6
    1 1
    C 340 50 10
    = 58.8 
    XL = L = 340 × 20 × 10-3 = 6.8 
    Z = + 
    2 2
    C LR (X X )
    = +  = 2 240 (58.8 6.8) 4304
    P = 2rmsi R =
     
      
    2
    rmsV R
    Z
    =
     
      
     
    2
    10 / 2
    4304
    × 40 =
    50 40
    4304
    = 0.47 W
    So best answer (nearest answer) will be (1)