Advertisements
Advertisements
Question
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
Solution
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
RELATED QUESTIONS
How would you connect two resistors in series? Draw a diagram. Calculate the total equivalent resistance.
Choose the correct alternative.
Which of the following is an ohmic conductor?
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?
State Ohm’s law? How can it be verified experimentally? Does it hold good under all conditions? Comment.
Calculate the total resistance of the circuit and find the total current in the circuit.
Ohm's law deals with the relationship between ______
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 ______.
What is the resistance of a conductor through which a current of 0.5 A flows when a potential difference of 2V is applied across its ends?
A current of 0.8 A flows in a conductor of 40 Ω for 1 minute. The heat produced in the conductor will be ______.
