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प्रश्न
The circuit depicted in the figure is employed for studying Ohm’s Law. Instead of using a standard resistor, a student opts for a glass tube filled with mercury (tube 1), connected to the circuit through two electrodes, E1 and E2. He records the readings of the ammeter and voltmeter, thereby calculating the resistance. The student repeats the experiment by substituting tube 1 with tube 2, where the same amount of mercury fills tube 2.
Neglecting internal resistance of the cell use (> or < or =) to compare:
- the resistance in both the cases.
- the voltmeter readings in both the cases.
- the specific resistance in both the cases.
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उत्तर
- The resistance of tube 2 is less than the resistance of tube 1 because resistance depends directly on the length and inversely on the area of the resistor, and tube 2 is thicker and shorter than tube 1.
- The voltmeter reading for tube 1 is the same as the voltmeter reading for tube 2 because, according to Ohm’s law, the potential difference across a resistor depends only on the current applied, not on the resistance of the resistor.
- As the specific resistance of a resistor is independent of its dimensions but depends only on the contained material, and since here both tubes contain only mercury, the specific resistance in both cases is the same.
संबंधित प्रश्न
Find the expression for the resistivity of a material and state the SI unit of resistivity.
State Ohm’s law and draw a neat labelled circuit diagram containing a battery, a key, a voltmeter, an ammeter, a rheostat and an unknown resistance to verify it.
- Draw a V-I graph for a conductor obeying Ohm’s law.
- What does the slope of V–I graph for a conductor represent?
A car bulb connected to a 12 volt battery draws 2 A current when glowing. What is the resistance of the filament of the bulb? Will the resistance be more same or less when the bulb is not glowing?
Choose the correct alternative.
Which of the following is an ohmic conductor?
SI unit of resistance is:
State macroscopic form of Ohm’s law.
Obtain the macroscopic form of Ohm’s law from its microscopic form and discuss its limitation.
Suppose there is a circuit consisting of only resistances and batteries and we have to double (or increase it to n-times) all voltages and all resistances. Show that currents are unaltered. Do this for circuit of Example 3.7 in the NCERT Text Book for Class XII.
The resistance of a resistor is reduced to half of its initial value. If other parameters of the electrical circuit remain unaltered, the amount of heat produced in the resistor will become ______.
