NEET-XII-Physics
32: Electric Current in Conductors
- #24The resistance of the rheostat shown in the figure (32-E5) is 30 Ω. Neglecting the meter resistance, find the
figure32-E5
minimum and maximum currents through the ammeter as the rheostat is varied.
Ans : Current will be minimum when the rheostat will have maximum resistance, i.e 30 Ω.
In this case, total resistance of the circuit = `` \frac{20\times 10}{30}+30=36.67\,\mathrm{\,\Omega \,}``
The minimum current through the circuit,
`` {i}_{\,\mathrm{\,min\,}}=\frac{5.5}{36.67}=0.15\,\mathrm{\,A\,}``
Current will be maximum when the rheostat will have minimum resistance, i.e. 0 Ω.
In this case, total resistance of the circuit = `` \frac{20\times 10}{30}=6.67\,\mathrm{\,\Omega \,}``
The maximum current through the circuit,
`` {i}_{\,\mathrm{\,max\,}}=\frac{5.5}{6.67}=0.825\,\mathrm{\,A\,}``
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