Advertisements
Advertisements
Question
Four resistances of 16 ohms each are connected in parallel. Four such combinations are connected in series. What is the total resistance?
Advertisements
Solution
When four resistors of 16 Ω each are connected in parallel, the effective resistance of the combination can be obtained as:
`1/R=1/R_1+1/R_2+1/R_3+1/R_4`
or `1/R=1/16+1/16+1/16+1/16`
or `1/R=4/16`
or `1/R=1/4`
or `R=4`Ω
The effective resistance of combination is 4 Î.
When four such combinations are connected in series, the effective resistance becomes:
R = R1 + R2+ R3 + R4
R = 4 Î + 4 Î + 4 Î + 4 Î = 16 Ω
APPEARS IN
RELATED QUESTIONS
Graph showing the variation of current versus voltage for a material Ga As is shown in the figure. Identify the region of
(i) negative resistance
(ii) where Ohm's law is obeyed.
Fill in the following blank with suitable words:
Resistance is measured in .............. The resistance of a wire increases as the length ..............; as the temperature ..............; and as the cross-sectional area .............. .
A resistance of 40 ohms and one of 60 ohms are arranged in series across 220 volt supply. Find the heat in joules produced by this combination of resistances in half a minute.
Calculate the current flowing through a wire of resistance 5 Ω connected to a battery of potential difference 3 V.
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?
Define the following:
Coulomb
Define ampere and volt with respect to Ohm’s law.
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.
What is ohmic device?
Define temperature coefficient of resistance.
Explain the equivalent resistance of a parallel resistor network.
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 variable resistance is called ____________.
A student carries out an experiment and plots the V-I graph of three samples of nichrome wire with resistances R1, R2 and R3 respectively. Which of the following is hue?
A student carries out an experiment and plots the V-I graph of three samples of nichrome wire with resistances R1, R2 and R3 respectively. Which of the following is true?
State Ohm’s law? How can it be verified experimentally? Does it hold good under all conditions? Comment.
A heater of 220 V heats a volume of water m 5 mint time. A heater of 110 V heat in ten second. The resistance of the conductor is
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.
A current of 3.2 mA flows through a conductor. If charge on an electron is −1.6 × 10-19 coulomb, find the number of electrons that will pass each second through the cross section of that conductor.
