Advertisements
Advertisements
प्रश्न
State the limitations of Ohm’s law.
उत्तर
There are two main limitations:
(i) Temperature,
(ii) Physical condition of the conductor.
It is found that the ratio V/I is mo longer constant when the temperature is not kept constant. Generally, resistance increases with the rise in the temperature of the conductor.
Physical conditions of any conductor mainly include:
(i) Its length,
(ii) Its cross-sectional area,
(iii) The kind of material.
If there is no change in any of the above three conditions and also other condition like temperature remains constant, then Ohm’s law holds good, i.e., the ratio V/I remains constant.
APPEARS IN
संबंधित प्रश्न
Why are coils of electric toasters and electric irons made of an alloy rather than a pure metal?
A low voltage supply from which one needs high currents must have very low internal resistance. Why?
Name the law which is illustrated by the above V−I graph.
Keeping the p.d. constant, the resistance of a circuit is halved. The current will become:
(a) one-fourth
(b) four time
(c) half
(d) double
The graph between V and I for a conductor is a straight line passing through the origin.
What should remain constant in a statement of this law?
- 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 wire of resistance 3 ohm and length 10 cm is stretched to length 30 cm. Assuming that it has a uniform cross section, what will be its new resistance?
State Ohm’s law.
Two cells each of 5V are connected in series across an 8Ω resistor and three parallel resistors of 4Ω, 6Ω, and 12Ω. Draw a circuit diagram for the above arrangement. Calculate
- the current drawn from the cell
- current through each resistor
The unit of specific resistance is ____________.
