Q26.A potentiometer wire of length 300 cm is connected in series with a resistance 780 Ω and a standard cell of emf 4 V. A constant current flows through potentiometer wire. The length of the null point for cell of emf 20mV is found to be 60 cm. The resistance of the potentiometer wire is _____ Ω.
What This Question Tests
This question tests the application of the potentiometer principle to find an unknown resistance by relating the potential drop across the wire to the null point length.
Concepts Tested
Formulas Used
V = E_cell
V = (E_driver / (R_wire + R_series)) * R_wire
V_null = (V/L) * l_null
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📋 Question Details
- Chapter
- Current Electricity
- Topic
- Potentiometer
- Year
- 2022
- Shift
- 26 Jul Shift 2
- Q Number
- Q26
- Type
- Numerical
- NCERT Ref
- Class 12 Physics Ch 3: Current Electricity
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