Advertisements
Advertisements
प्रश्न
Three cells, each of emf E but internal resistances 2r, 3r and 6r are connected in parallel across a resistor R.
Obtain expressions for (i) current flowing in the circuit, and (ii) the terminal potential differences across the equivalent cell.
उत्तर
`R_{AB}` = ?
`1/(R_{AB}) = 1/(2r) + 1/(3r) + 1/(6r)`
`1/R_{AB} = 1/r[(3 + 2 + 1)/6]`
`1/R_{AB} = 1/r`
`R_{AB} = r` ⇒ equivalent internal resistant
Equivalent emf of cells in parallel,
`E_{eq} = (E_1/r_1 + E_2/r_2 + E_3/r_3)/(1/r_1 + 1/r_2 + 1/r_3)`
= `(E/(2r) + E/(3r) + E/(6r))/(1/(2r) + 1/(3r) + 1/(6r))`
`E_{eq} = E[(1/(2r) + 1/(3r) + 1/(6r))/(1/(2r) + 1/(3r) + 1/(6r))]`
Eeq = E
Current flowing in the circuit,
I = `E_{eq}/(R + R_{AB})`
I = `E/(R + r)`
Potential drop across E,
V = IReq
V = `(rE)/(R + r)`
APPEARS IN
संबंधित प्रश्न
Six lead-acid types of secondary cells each of emf 2.0 V and internal resistance 0.015 Ω are joined in series to provide a supply to a resistance of 8.5 Ω. What are the current drawn from the supply and its terminal voltage?
Nichrome and copper wires of same length and same radius are connected in series. Current I is passed through them. Which wire gets heated up more? Justify your answer.
A 10 V cell of negligible internal resistance is connected in parallel across a battery of emf 200 V and internal resistance 38 Ω as shown in the figure. Find the value of current in the circuit.
A cell of emf ‘E’ and internal resistance ‘r’ draws a current ‘I’. Write the relation between terminal voltage ‘V’ in terms of E, I and r ?
A cell of emf E and internal resistance r is connected to two external resistance R1 and R2 and a perfect ammeter. The current in the circuit is measured in four different situations:
(i) without any external resistance in the circuit
(ii) with resistance R1 only
(iii) with R1 and R2 in series combination
(iv) with R1 and R2 in parallel combination
The currents measured in the four cases are 0.42 A, 1.05 A, 1.4 A and 4.2 A, but not necessarily in the order. Identify the currents corresponding to the four cases mentioned above.
Do all thermocouples have a neutral temperature?
A coil of resistance 100 Ω is connected across a battery of emf 6.0 V. Assume that the heat developed in the coil is used to raise its temperature. If the heat capacity of the coil is 4.0 J K−1, how long will it take to raise the temperature of the coil by 15°C?
Answer the following question.
A cell of emf E and internal resistance r is connected across a variable resistor R. Plot the shape of graphs showing a variation of terminal voltage V with (i) R and (ii) circuit current I.
Five cells each of emf E and internal resistance r send the same amount of current through an external resistance R whether the cells are connected in parallel or in series. Then the ratio `("R"/"r")` is:
The internal resistance of a cell is the resistance of ______
