Question

2. Three resistors of 202,40 and 60 are connected in parallel. The 40 Q resistor has 1.0 A flowing through it. What are the currents through the 20 and 60 resistors? 3. If you wish to increase the current passing through the circuit in the previous question by adding another battery, would you add it in series or in parallel to the existing one. SERIES PARALLEL 4. In which case will more current flow through the battery: when three identical resistors are connected in series with the battery, or when the same three resistors are connected in parallel with the battery. SERIES PARALLEL 5. How would you explain in simple words to a layman that adding resistors in parallel reduced=s the overall resistance while adding them in series increases it don't explain through equations)

Answer 1

2)

$20\,\Omega,40\,\Omega,60\Omega$ resistances are in parallel. Voltage across the resistors is same.

Current through $40\,\Omega$ is $I_2=1.0\,A$

$I_1=\frac{40I_2}{20}=\frac{40*1.0}{20}=2.0\,A$

$I_3=\frac{40I_2}{60}=\frac{40*1.0}{60}=0.67\,A$

Current through $20\,\Omega$ is

Current through $60\,\Omega$ is

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3)

To increase the current in the circuit, a batter must be added in series to the previous battery.

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4)

When identical resistors are connected in series, total resistance in the circuit is increased, and current through the circuit is less.

When the identical resistances are connected in parallel, total resistance in the circuit is decreased, the current through the circuit is more.

More current flows through the battery when resistors are in parallel.

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5)

Imagine a forest with a large number of trees and a group of people were asked to run from one end of forest to the other.

The force with which you order them to run is " voltage ". When a person runs through a forest he cannot run in a straight path. because he may collide with trees. Hence every instant the person changes his direction of running to avoid hitting the trees. The rate at which people reach the other side is " current ".

And the effect of forest is " resistance". When the distance between the two ends of forest is increased by adding more trees , the rate at which the people reach the other side will decrease. that is by adding resistances in series , total resistance ( effect of all the forest) increases.

When the width ( length of forest perpendicular to direction of movement of persons)of the forest is less, rate at which the persons reaching the other end will be less.total resistance ( effect of all the forest) increases.

When width is increased, the rate at which the people reach the other end is more. Hence by adding resistances in parallel the total resistance( effect of all the forest) decreases.

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