Advertisements
Advertisements
प्रश्न
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?
Advertisements
उत्तर
Available resistances = 220 Ω, 79 Ω 92 Ω
Case I:
If 3 resistors are connected in series, then
RS = R1 + R2 + R3 = 220 + 79 + 92 = 391
This value is greater than the required resistance so it is not possible.
Case II:
If 3 resistors are connected in parallel, then
`1/"R"_"p" = 1/"R"_1 + 1/"R"_2 + 1/"R"_3`
`1/"R"_"p" = 1/220 + 1/79 + 1/92` = 0.0279
Rp = 35.84 This does not meet the requirement.
Case III:
If R1 and R2 are connected in parallel and R3 in series
`1/"R"_"p" = 1/"R"_1 + 1/"R"_2 = 1/220 + 1/79 = 0.0172`
`=> "R"_"p" = 58.14 Omega`
This meets the requirement.
APPEARS IN
संबंधित प्रश्न
Will current flow more easily through a thick wire or a thin wire of the same material, when connected to the same source? Why?
What is Resistivity?
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 unit of electrical resistance is:
(a) ampere
(b) volt
(c) coulomb
(d) ohm
Two metallic spheres A and B kept on insulating stands are in contact with each other. A positively charged rod P is brought near the sphere A as shown in the figure. The two spheres are separated from each other, and the rod P is removed. What will be the nature of charges on spheres A and B?
Fig. represents the circuit used for the verification of Ohm's law. Label the parts from A to F. state the function of each.
State the limitations of Ohm’s law.
What are ohmic conductors? Give one exmaple. Draw a graph showing the current-voltage relationship for an ohmic conductor.
Define temperature coefficient of resistance.
Write a short note on superconductors?
