Advertisements
Advertisements
प्रश्न
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 ______.
विकल्प
maximum when the battery is connected across 1 cm × `1/2` cm faces.
maximum when the battery is connected across 10 cm × `1/2` cm faces.
maximum when the battery is connected across 10 cm × `1/2` cm faces.
same irrespective of the three faces.
Advertisements
उत्तर
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 maximum when the battery is connected across 1 cm × `1/2` cm faces.
Explanation:
The resistance of a wire depends on various parameters, its area, material (resistivity) and length (length of the rod).
Here, the metallic rod behaves as a wire.
The relationship between resistance and various parameter is given by R = ρl/A.
The resistance of a wire is given by R = `p l/A`
For greater value of R, l must be higher and A should be lower and it is possible only when the battery is connected across 1 cm × `(1/2)` cm (area of corss-section A).
APPEARS IN
संबंधित प्रश्न
A low voltage supply from which one needs high currents must have very low internal resistance. Why?
The relationship between the potential difference and the current in a conductor is stated in the form of a law.
1) Name the law.
2) What does the slope of V-I graph for a conductor represent?
3) Name the material used for making the connecting wire.
Write the formula of resistivity
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?
In an experiment of verification of Ohm’s law following observations are obtained.
|
Potential difference V (in volt) |
0.5 | 1.0 | 1.5 | 2.0 | 2.5 |
| current I (in ampere) | 0.2 | 0.4 | 0.6 | 0.8 | 1.0 |
Draw a V-I graph and use this graph to find:
- the potential difference V when the current I is 0.5 A,
- the current I when the potential difference V is 0.75 V,
- the resistance in a circuit.
How would you connect two resistors in series? Draw a diagram. Calculate the total equivalent resistance.
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.
- Name and state the law which relates the potential difference and current in a conductor.
- What is the necessary condition for a conductor to obey the law named above in part (a) ?
What is meant by the drift speed of free electrons?
State and define Ohm’s law.
What are ohmic conductors? Give one exmaple. Draw a graph showing the current-voltage relationship for an ohmic conductor.
Draw a neat diagram for the verification of Ohm’s law by voltmeter-ammeter method. By another diagram show the relation between p.d. and current.
A wire connected to a power supply of 230 V has power dissipation P1. Suppose the wire is cut into two equal pieces and connected parallel to the same power supply. In this case, power dissipation is P2. The ratio of `"P"_2/"P"_1` is
Define Current density.
State macroscopic form of Ohm’s law.
Write a short note on superconductors?
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.
Ohm's law deals with the relationship between ______
