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प्रश्न
Explain why potential difference is always less than the e.m.f. of a cell?
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उत्तर
When a cell is in closed circuit, i.e., when current is drawn from it, then the potential difference between its electrodes is called the terminal voltage. It is always less than the e.m.f. because when charge flows in a circuit, some energy is spent in the flow of charge through the electrolyte of the cell.
संबंधित प्रश्न
The values of current I flowing in a given resistor for the corresponding values of potential difference V across the resistor are given below:
| I (amperes) | 0.5 | 1.0 | 2.0 | 3.0 | 4.0 |
| V (volts) | 1.6 | 3.4 | 6.7 | 10.2 | 13.2 |
Plot a graph between V and I and calculate the resistance of that resistor.
If a potential difference of 10 V causes a current of 2 A to flow for 1 minute, how much energy is transferred?
A resistance of 20 ohms has a current of 2 amperes flowing in it. What potential difference is there between its ends?
A p.d. of 10 V is needed to make a current of 0.02 A flow through a wire. Wire p.d. is needed to make a current of 250 mA flow through the same wire?
Explain the statement ‘the potential difference between two points is 1 volt’.
A V-I graph for a nichrome wire is given below. What do you infer from this graph? Draw a labelled circuit diagram to obtain such a graph.
Three resistors are connected to a 12 V battery as shown in the figure given below:
(i) What is the current through the 8 ohm resistor?
(ii) What is the potential difference across the parallel combination of 6 ohm and 12 ohm resistor?
(iii) What is the current through the 6 ohm resistor?
State Ohm’s law.
Study the following circuit and find:
- Effective resistance of the circuit
- Current drawn from the battery
- Potential difference across the 5 omega resistor
What does the positive and negative sign of potential convey?
