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प्रश्न
What is Resistivity?
उत्तर
The resistivity of a conductor is defined as the resistance of a conductor of unit length and unit area of cross-section.
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संबंधित प्रश्न
If the potential difference across the ends of a conductor is 220 V and the resistance of the conductor is 44 Ω (ohm), then the current flowing through is _________.
- 0.2 A
- 0.5 A
- 2 A
- 5 A
What will be the change in the current if the potential difference is kept constant and the resistance of the circuit is made four times?
- It will remain unchanged.
- It will become four times.
- It will become one-fourth.
- It will become half.
Graph showing the variation of current versus voltage for a material Ga As is shown in the figure. Identify the region of
(i) negative resistance
(ii) where Ohm's law is obeyed.
Will current flow more easily through a thick wire or a thin wire of the same material, when connected to the same source? Why?
Is Ohm’s law universally applicable for all conducting elements? If not, give examples of elements which do not obey Ohm’s law.
A low voltage supply from which one needs high currents must have very low internal resistance. Why?
Write the SI unit of resistivity
An electrical bulb is marked 200V, 100W. Calculate the electrical resistance of its filament. If five such
bulbs are connected in series to a 200V supply, how much current will flow through them?
Name the unit of electrical resistance and give its symbol.
When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Calculate the value of the resistance of the resistor.
Name the law which is illustrated by the above V−I graph.
Ohm's law gives a relationship between:
(a) current and resistance
(b) resistance and potential difference
(c) potential difference and electric charge
(d) current and potential difference
The graph between V and I for a conductor is a straight line passing through the origin.
Which law is illustrated by such a graph?
How should the two resistances of 2 ohms each be connected so as to produce an equivalent resistance of 1 ohm?
Four resistances of 16 ohms each are connected in parallel. Four such combinations are connected in series. What is the total resistance?
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.
In a conductor 6.25 × `10^16` electrons flow from its end A to B in 2 s. Find the current flowing through the conductor (e = 1.6 × `10^-19` C)
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?
What length of copper wire of resistivity 1.7 × 10-8 Ω m and radius 1 mm is required so that its resistance is 2Ω?
A wire has a length of 2.0 m and a resistance of 5.0 Ω. Find the electric field existing inside the wire if it carries a current of 10 A.
Fig. represents the circuit used for the verification of ohm's law. Label the different parts from A and F. State the function of each.
Tick(✓) the correct choice in the following:
Ohm's law is applicable to
Rewrite the following statement by selecting the correct option.
The S.I. unit of resistance is __________.
State and define Ohm’s law.
Define ampere and volt with respect to Ohm’s law.
Choose the correct alternative.
Which of the following is an ohmic conductor?
Answer the following question.
Distinguish between Ohmic and non-ohmic substances; explain with the help of example.
Obtain the macroscopic form of Ohm’s law from its microscopic form and discuss its limitation.
Explain the equivalent resistance of a series resistor network.
The resistance of a nichrome wire at 0°C is 10Ω. If its temperature coefficient of resistivity of nichrome is 0.004/ °C, find its resistance of the wire at boiling point of water. Comment on the result.
An electronics hobbyist is building a radio which requires 150 Ω in her circuit, but she has only 220 Ω, 79 Ω, and 92 Ω resistors available. How can she connect the available resistors to get the desired value of resistance?
The temperature of a conductor is increased. The graph best showing the variation of its resistance is:
The heat produced by a 100 w heater in 2 minute is equal to
A metal rod of length 10 cm and a rectangular cross-section of 1 cm × `1/2` cm is connected to a battery across opposite faces. The resistance will be ______.
