Advertisements
Advertisements
प्रश्न
The circuit in figure shows two cells connected in opposition to each other. Cell E1 is of emf 6V and internal resistance 2Ω; the cell E2 is of emf 4V and internal resistance 8Ω. Find the potential difference between the points A and B.
Advertisements
उत्तर
In this problem, after finding the electric current flow in the circuit by using Kirchoff’s law or Ohm’s law, the potential difference across AB can be obtained.
Applying Ohm's law.
Equivalent emf of two cells = 6 – 4 = 2V and equivalent resistance = 2Ω + 8Ω = 10Ω, so the electric current is given by
`I = (6 - 4)/(2 + 8)` = 0.2 A
Taking loop in anti-clockwise direction, since E1 > E2
The direction of flow of current is always from high potential to low potential.
Therefore VB > VA.
⇒ VB – 4V – (0.2) × = VA
Therefore, VB – VA = 3.6V
Important point: Sign convention for the application of Kirchoff’s law: For the application of Kirchoff’s laws following sign convention are to be considered.
(i) The change in potential in traversing a resistance in the direction of current is – iR while in the opposite direction + iR.
(ii) The change in potential in traversing as emf source from negative to positive terminal is +E while in the opposite direction – E irrespective of the direction of current in the circuit.
APPEARS IN
संबंधित प्रश्न
Kirchhoff's junction law is equivalent to .............................
(a) conservation of energy.
(b) conservation of charge
(c) conservation of electric potential
(d) conservation of electric flux
Use Kirchhoff's rules to obtain conditions for the balance condition in a Wheatstone bridge.
Given n resistors each of resistance R, how will you combine them to get the (i) maximum (ii) minimum effective resistance? What is the ratio of the maximum to minimum resistance?
Given the resistances of 1 Ω, 2 Ω, 3 Ω, how will be combine them to get an equivalent resistance of (11/3) Ω?
Given the resistances of 1 Ω, 2 Ω, 3 Ω, how will be combine them to get an equivalent resistance of (11/5) Ω?
Given the resistances of 1 Ω, 2 Ω, 3 Ω, how will be combine them to get an equivalent resistance of 6 Ω?
Given the resistances of 1 Ω, 2 Ω, 3 Ω, how will be combine them to get an equivalent resistance of (6/11) Ω?
Using Kirchhoff’s rules determine the value of unknown resistance R in the circuit so that no current flows through 4 Ω resistance. Also find the potential difference between A and D.
A capacitor of capacitance 8.0 μF is connected to a battery of emf 6.0 V through a resistance of 24 Ω. Find the current in the circuit (a) just after the connections are made and (b) one time constant after the connections are made.
State Kirchhoff ’s voltage rule.
Obtain the condition for bridge balance in Wheatstone’s bridge.
The instrument for the accurate measurement of the e.m.f of a cell is ______.
The Kirchhoff's second law (ΣiR = ΣE), where the symbols have their usual meanings, is based on ______.
The e.m.f of The battery in a thermocouple is doubled. The rate of heat generated at one of the junction will.
Kirchhoff’s junction rule is a reflection of ______.
- conservation of current density vector.
- conservation of charge.
- the fact that the momentum with which a charged particle approaches a junction is unchanged (as a vector) as the charged particle leaves the junction.
- the fact that there is no accumulation of charges at a junction.
Two cells of voltage 10V and 2V and internal resistances 10Ω and 5Ω respectively, are connected in parallel with the positive end of 10V battery connected to negative pole of 2V battery (Figure). Find the effective voltage and effective resistance of the combination.
