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NEET-XII-Physics

32: Electric Current in Conductors

with Solutions - page 6
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  • #32
    Consider the circuit shown in the figure (32-E8). Find the current through the 10 Ω resistor when the switch S is (a) open (b) closed.
    figure32-E8
    Ans : (a) When S is open, the resistors will be connected in series, as the current will flow through the 20 Ω resistor. The effective resistance,
    `` {\,\mathrm{\,R\,}}_{\,\mathrm{\,eff\,}}=\left(10+20\right)\,\mathrm{\,\Omega \,}=30\,\mathrm{\,\Omega \,}``
    `` ``
    The current flowing through the circuit,
    `` i=\left(\frac{3}{30}\right)\,\mathrm{\,A\,}=0.1\,\mathrm{\,A\,}`` (b) When S is closed, current will flow through the switch that offers the least resistive path. So, the 20 Ω resistance will be ineffective in this case. The effective resistance in this case,
    `` {R}_{\,\mathrm{\,eff\,}}=10\,\mathrm{\,\Omega \,}``
    `` ``
    The current flowing through the circuit,
    `` i=\left(\frac{3}{10}\right)\,\mathrm{\,A\,}=0.3\,\mathrm{\,A\,}``
    Page No 200:
  • #32-a
    open
    Ans : When S is open, the resistors will be connected in series, as the current will flow through the 20 Ω resistor. The effective resistance,
    `` {\,\mathrm{\,R\,}}_{\,\mathrm{\,eff\,}}=\left(10+20\right)\,\mathrm{\,\Omega \,}=30\,\mathrm{\,\Omega \,}``
    `` ``
    The current flowing through the circuit,
    `` i=\left(\frac{3}{30}\right)\,\mathrm{\,A\,}=0.1\,\mathrm{\,A\,}``
  • #32-b
    closed.
    figure32-E8
    Ans : When S is closed, current will flow through the switch that offers the least resistive path. So, the 20 Ω resistance will be ineffective in this case. The effective resistance in this case,
    `` {R}_{\,\mathrm{\,eff\,}}=10\,\mathrm{\,\Omega \,}``
    `` ``
    The current flowing through the circuit,
    `` i=\left(\frac{3}{10}\right)\,\mathrm{\,A\,}=0.3\,\mathrm{\,A\,}``
    Page No 200: