Physics-
General
Easy

Question

When a certain circuit consisting of a constant e.m.f. E an inductance L and a resistance R is closed, the current in, it increases with time according to curve 1. After one parameter (E, L or R) is changed, the increase in current follows curve 2 when the circuit is closed second time. Which parameter was changed and in what direction

  1. L is increased    
  2. L is decreased    
  3. R is increased    
  4. R is decreased    

The correct answer is: L is increased


    fraction numerator d i over denominator d t end fraction equalsslope of i – t graph slope of graph (b) < slope of graph (a) so open parentheses fraction numerator d i over denominator d t end fraction close parentheses subscript 2 end subscript less than open parentheses fraction numerator d i over denominator d t end fraction close parentheses subscript 1 end subscript
    Also L proportional to fraction numerator 1 over denominator left parenthesis d i divided by d t right parenthesis end fraction rightwards double arrow L subscript 2 end subscript greater than L subscript 1 end subscript

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