Advertisements
Advertisements
प्रश्न
The filament of a bulb takes a current 100 mA when potential difference across it is 0.2 V. When the potential difference across it becomes 1.0 V, the current becomes 400 mA. Calculate the resistance of filament in each case and account for the difference.
Advertisements
उत्तर
According to Ohm's law,
V = IR
∴ R = `"V"/"I"`
`therefore "R"_1 = "V"_1/"I"_1`
= `0.2/0.1 = 2 Omega`
Similarly ,
`"R"_2 = "V"_2/"I"_2`
= `1/0.4`
= 2.5 Ω
Resistance of the wire increases with increase in temperature. So the difference arises because the temperature of the filament increased.
APPEARS IN
संबंधित प्रश्न
The unit of electrical resistance is:
(a) ampere
(b) volt
(c) coulomb
(d) ohm
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?
What is the necessary condition for a conductor to obey Ohm’s law?
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 parts from A to F. state the function of each.
What are ohmic conductors? Give one exmaple. Draw a graph showing the current-voltage relationship for an ohmic conductor.
Write a short note on superconductors?
You are provided with a resistor, a key, an ammeter, a voltmeter, four cells of 1.5 V each and few connecting wires. Using circuit components, draw a labelled circuit diagram to show the setup to study Ohm's law.
State the relationship between potential difference (V) across the resistor and the current (I) flowing through it. Also draw V-I graph, taking V on the X-axis.
Let the resistance of an electrical device remain constant, while the potential difference across its two ends decreases to one fourth of its initial value. What change will occur in the current through it? State the law which helps us in solving the above stated question.
