Q18.A potentiometer PQ is set up to compare two resistances, as shown in the figure. The ammeter A in the circuit reads 1. 0 A when the two-way key K3 is open. The balance point is at a length l1 cm from P when the two- way key K3 is plugged in between 2 and 1 , while the balance point is at a length l2 cm from P when the key K3 is plugged in between 3 and 1 . The ratio of two resistances R1R2 , is found to be (1) l1 (2) l2 l1−l2 l2−l1 (3) l1 (4) l1 l1+l2 l2−l1
What This Question Tests
This question tests the application of the potentiometer principle to compare two unknown resistances by finding the balance points corresponding to the voltage drops across them.
Concepts Tested
Formulas Used
V ∝ l
V_R1 / V_R2 = R1 / R2
R1/R2 = l1/l2
📚 NCERT Sections This Tests
4.10 — Two Moving Coil Meters, M1 And M2 Have The Following Particulars:
Physics Class 11 · Chapter 4
4.10 Two moving coil meters, M1 and M2 have the following particulars: R1 = 10 Ω, N1 = 30, A1 = 3.6 × 10–3 m2, B1 = 0.25 T R2 = 14 Ω, N2 = 42, A2 = 1.8 × 10–3 m2, B2 = 0.50 T (The spring constants are identical for the two meters). Determine the ratio of (a) current sensitivity and (b) voltage sensitivity of M2 and M1.
3.2 — A Battery Of Emf 10 V And Internal Resistance 3 Ω Is Connected To A
Physics Class 11 · Chapter 3
3.2 A battery of emf 10 V and internal resistance 3 Ω is connected to a resistor. If the current in the circuit is 0.5 A, what is the resistance of the resistor? What is the terminal voltage of the battery when the circuit is closed?
2.1 — Two Charges 5 × 10–8 C And –3 × 10–8 C Are Located 16 Cm Apart. At
Physics Class 11 · Chapter 2
2.1 Two charges 5 × 10–8 C and –3 × 10–8 C are located 16 cm apart. At what point(s) on the line joining the two charges is the electric potential zero? Take the potential at infinity to be zero.
📋 Question Details
- Chapter
- Current Electricity
- Topic
- Potentiometer
- Year
- 2017
- Shift
- 08 Apr Online
- Q Number
- Q18
- Type
- MCQ
- NCERT Ref
- Class 12 Physics Ch 3: Current Electricity
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