Advertisements
Advertisements
प्रश्न
A cell supplies a current of 0.6 A through a 2Ω coil and a current of 0.3 A through on 8Ω coil. Calculate the e.m.f and internal resistance of the cell.
Advertisements
उत्तर
Given: I1 = 0.6 A, R1 = 2 Ω and I2 = 0.3 A, R2 = 8 Ω
Let the e.m.f. of the cell is E and its internal resistance is r.
From I = `"E"/("R + r")`
0.6 = `"E"/("2 + r")` and `0.3 = "E"/("8 + r")`
∴ E = 0.6 (2 + r) = 1.2 + 0.6 r and
E = 0.3 (8 + r) = 2.4 + 0.3r
Thus, 1.2 + 0.6r = 2.4 + 0.3r
or 0.6r - 0.3r = 2.4 - 1.2
Or 0.3 r = 1.2 or
r = `1.2/0.3 = 4 Omega`.
and E = 1.2 + 0.6 × 4 = 1.2 + 2.4 = 3.6 V
संबंधित प्रश्न
What happens to the resistivity of semiconductor with the increase of temperature?
A cell of Emf 2 V and internal resistance 1.2 Ω is connected with an ammeter of resistance 0.8 Ω and two resistors of 4.5 Ω and 9 Ω as shown in the diagram below:
1) What would be the reading on the Ammeter?
2) What is the potential difference across the terminals of the cell?
The diagram below in Fig. 8.40 shows a cell of e.m.f. ε = 2 volt and internal resistance r = 1 ohm to an external resistance R = 4 ohm. The ammeter A measures the current in the circuit and the
voltmeter V measures the terminal voltage across the cell. What will be the readings of the ammeter and voltmeter when (i) the key K is open, (ii) the key K is closed.
A battery of e.m.f 3.0 V supplies current through a circuit in which the resistance can be changed.
A high resistance voltmeter is connected across the battery. When the current is 1.5 A, the voltmeter reads 2.7 V. Find the internal resistance of the battery.
A cell of e.m.f. 2 V and internal resistance 1.2 Ω is connected to an ammeter of resistance 0.8 Ω and two resistors of 4.5 Ω and 9 Ω as shown in following figure.
Find:
- The reading of the ammeter,
- The potential difference across the terminals of the cells, and
- The potential difference across the 4.5 Ω resistor.
What is the colour code for the insulation on the earth wire?
A cell of emf. 1.5 V and internal resistance 10 ohms is connected to a resistor of 5 ohms, with an ammeter in series see fig.. What is the reading of the ammeter?
When a resistance of 3Ω is connected across a cell, the current flowing is 0.5 A. On changing the resistance to 7Ω, the current becomes 0.25A. Calculate the e.m.f. and the internal resistance of the cell.
Study the diagram:
- Calculate the total resistance of the circuit.
- Calculate the current drawn from the cell.
- State whether the current through 10 Ω resistor is greater than, less than or equal to the current through the 12 Ω resistor.
A battery of e.m.f. 6.0 V supplies current through a circuit in which the resistance can be changed. A high resistance voltmeter is connected across the battery. When the current is 3 A, the voltmeter reads 5.4 V. Find the internal resistance of the battery.
