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KVPY2015PhysicsCurrent Electricity

A light bulb of resistance R=16 is attached in series with an infinite resistor network. with identical resistances r as shown below. A 10 ~V battery derives current in the circuit. What should be the value of r such that the bulb dissipated about 1 ~W of power.

Options

  1. A14.8
  2. B29.6
  3. C7.4
  4. D3.7

Correct answer

A. 14.8

Step-by-step solution

array l P _ bulb = v² R =i² R 1= v² 16 ~V _ B =4 ~V 1=i² 16 I _ B = 1 4 Amp . 6= 1 4 r_ e q ( equivalent of groups of r ) array Where r_ e q =r+ r_ e q r r_ e q +r

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