Electrical Circuit | Numerical Solution

2075 S / 2067 B

In the adjacent circuit find, (i) the current in resistor $R$, (ii) the unknown emf $E$, (iii) the resistance $R$ (iv) if the circuit is broken at $P$, what is the current in resistor $R$?  

 [Click here for solution]

[2074 Supp]
A potentiometer is 10 m long. It has a resistance of 20 Ω. It is connected in series with a battery of 3 V and a resistance of 10 Ω. What is the potential gradient along with wire? [Click here for solution]

2074 A 

What must be the emf E in the circuit so that the current flowing through the $7 \Omega$ resistor is $1.80\;A$? Each emf source has negligible internal resistance. 

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[2072 Supp]
A simple potentiometer circuit is a setup as in figure, using uniform wire AB, 1m long, which has a resistance of 2 Ω. The resistance of the 4 V battery is negligible. If the variable resistor R were given a value of 2.4 Ω, what would be the length AC for zero galvanometer deflection? [Click here for solution]

2072 D 

A battery of $6 \; V$ and internal resistance $0.5\; \Omega$ is joined in parallel with another of $10\;V$ and internal resistance $1\;\Omega$. The combination sends a current through an external resistance of $12\; \Omega$. Find the current through each battery. [Click here for solution]

 

[2072 E]
The total length of the wire of a potentiometer is 10 m. A potential gradient of 0.0015 V/cm is obtained when a steady current is passed through this wire . Calculate:  

a) The distance of the null point on connecting standard cell of 1.018 V.
b) The unknown p.d. if the null point is obtained at a distance of 940 cm
c) The maximum p.d. which can be measured by this instrument. [Click here for solution]

2071 C 

 

Using Kirchhoff's laws of current and voltage, find the current in $2 \; \Omega$ resistor in the given circuit. [Click here for solution]

 

[2064, 2063, 2056]
The driver cell of a potentiometer has an e.m.f. of 2 V and negligible internal resistance. The potentiometer wire has a resistance of 3 Ω. Calculate the resistance needed in series with the wire if a pd 5 mV is required across the whole wire. The wire is 100 cm long and a balanced length of 60 cm is obtained for a thermocouple of emf E. What is the value of E? [Click here for solution]

 

[2059]

The e.m.f of a battery A is balanced by a length 75 cm on a potentiometer wire. The emf of a standard cell 1.02 V is balanced by a length of 50 cm. What is the emf of A? [Click here for solution]

 

[2056]

The driver cell of a potentiometer has an e.m.f. of 2 V and negligible internal resistance. The potentiometer wire has a resistance of 3 Ω. Calculate the resistance needed in series with the wire if a p.d. of 1.5 mV is required across the whole wire. [Click here for solution] 

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