10th Class Science Electricity and Circuits Question Bank Electricity

  • question_answer
    The ratings of three bulbs P, Q and R are given below.
    P : 120V, 24W
    Q : 120V, 60W
    R : 240V, 60W
    Which of the following represents the ascending order of their resistance?

    A) P, Q, R                                 

    B) Q, P, R                 

    C) R, P, Q                                 

    D) Q, R, P

    Correct Answer: B

    Solution :

     
    P \[R=\frac{{{(120)}^{2}}}{24}=600\,\Omega \]
    Q \[R=\frac{{{(120)}^{2}}}{60}=240\,\Omega \]
    R \[R=\frac{{{(240)}^{2}}}{60}=960\,\Omega \]
    \[\therefore \]The ascending order of values of resistances is Q, P, R.


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