Advertisements
Advertisements
प्रश्न
The plot of the variation of potential difference across a combination of three identical cells in series, versus current is shown below. What is the emf and internal resistance of each cell ?
Advertisements
उत्तर १
Let E and r be the EMF and internal resistance of all cells respectively and e and r' be the EMF and internal resistance of each cell respectively.
As we know,
According to the definition of the terminal potential difference,
V = E − Ir
E is the EMF and r is the total internal resistance of the circuit.
I = 0 ⇒ V = E
From the graph we can see
E = 6 V
As there are three cells we can write,
E = 3 × e ⇒ e = 2 V
And, when, V = 0
⇒ E = Ir
`r=E/T=6/1=6Omega`
As per the question the cells are connected in the series, so we can write.
`r'=r/3=2Omega`
उत्तर २
Since there are three cells connected in series, Total EMF = E1 + E2 + E3
We can observe from the graph that,
E1 + E2 + E3 = 6
3E = 6 (E = E1 = E2 = E3, as they are identical cells)
hence, The EMF of each cell is 2Volt.
Now, similarly, the internal resistance is also 2 Ohm for each, because in series combination of cells not only the Emf the internal resistance also gets added up.
APPEARS IN
संबंधित प्रश्न
Two cells of emfs 1.5 V and 2.0 V, having internal resistances 0.2 Ω and 0.3 Ω, respectively, are connected in parallel. Calculate the emf and internal resistance of the equivalent cell.
The equivalent resistance between points. a and f of the network shown in Figure 2 is :
a) 24 Ω
b) 110 Ω
c) 140 Ω
d) 200 Ω
The following figure shows an arrangement to measure the emf ε and internal resistance r of a battery. The voltmeter has a very high resistance and the ammeter also has some resistance. The voltmeter reads 1.52 V when the switch S is open. When the switch is closed, the voltmeter reading drops to 1.45 V and the ammeter reads 1.0 A. Find the emf and the internal resistance of the battery.
Find the value of i1/i2 in the following figure if (a) R = 0.1 Ω (b) R = 1 Ω and (c) R = 10 Ω. Note from your answers that in order to get more current from a combination of two batteries, they should be joined in parallel if the external resistance is small and in series if the external resistance is large, compared to the internal resistance.
How many time constants will elapse before the power delivered by a battery drops to half of its maximum value in an RC circuit?
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?
A conductor of length ‘l’ is rotated about one of its ends at a constant angular speed ‘ω’ in a plane perpendicular to a uniform magnetic field B. Plot graphs to show variations of the emf induced across the ends of the conductor with
- angular speed ω and
- length of the conductor l.
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:
A battery of EMF 10V sets up a current of 1A when connected across a resistor of 8Ω. If the resistor is shunted by another 8Ω resistor, what would be the current in the circuit? (in A)
