$CATEGORY: Science - Khan Academy/12.Electricity/12.Electricity--Resistance of a system of Resistors

//Multiple Choice

When two resistors are connected in parallel, the total resistance is always\: {
    ~Greater than the largest resistor
    ~Equal to the sum of the resistances
    =Less than the smallest resistor
    ~Equal to the largest resistor
}

The reciprocal of the equivalent resistance in a parallel circuit is given by\: {
    ~Req \= R1 + R2
    =1/Req \= 1/R1 + 1/R2
    ~Req \= (R1*R2)/(R1+R2)
    ~Req \= (R1+R2)/2
}

If three resistors of 6Ω, 3Ω, and 2Ω are connected in parallel, the equivalent resistance is\: {
    =1Ω
    ~2Ω
    ~3Ω
    ~6Ω
}

In a parallel circuit, the voltage across each resistor is\: {
    =The same
    ~Different for each resistor
    ~Equal to the total current
    ~Zero
}

The total current in a parallel circuit is\: {
    =The sum of the currents through each resistor
    ~Equal to the smallest current
    ~Equal to the largest current
    ~The product of individual currents
}

If a 10Ω and a 20Ω resistor are connected in parallel, the equivalent resistance is\: {
    ~30Ω
    =6.67Ω
    ~15Ω
    ~10Ω
}

If one branch in a parallel circuit is removed, the total resistance\: {
    =Increases
    ~Decreases
    ~Remains the same
    ~Becomes zero
}

A parallel circuit is preferred in household wiring because\: {
    ~It saves electricity
    =Each appliance gets the same voltage
    ~It increases resistance
    ~It reduces power consumption
}

In a parallel circuit, the power dissipation is\: {
    =Sum of the power dissipated by each resistor
    ~Less than the sum of individual power dissipation
    ~Equal to the square of the total resistance
    ~Zero
}

What happens to the total resistance when more resistors are added in parallel? {
    ~Increases
    =Decreases
    ~Remains the same
    ~Becomes infinite
}

//True or False

The voltage across each resistor in a parallel circuit is the same. {T}

Adding more resistors in parallel increases the total resistance. {F}

In a parallel circuit, current divides among the resistors. {T}

The total power in a parallel circuit is less than the sum of individual powers. {F}

The resistance of a parallel circuit is always greater than any individual resistance. {F}

//Fill in the blanks

The total resistance in a parallel circuit is always _____ than the smallest resistance. {
    ~greater
    =smaller
    ~equal
    ~None of the above
}

The reciprocal of total resistance in a parallel circuit is the _____ of the reciprocals of individual resistances. {
    =sum
    ~difference
    ~product
    ~None of the above
}

In a parallel circuit, voltage across each resistor is _____. {
    =same
    ~different
    ~zero
    ~None of the above
}

Adding more resistors in parallel _____ the total resistance. {
    ~increases
    =decreases
    ~does not change
    ~None of the above
}

The unit of resistance is _____. {
    ~Volt
    ~Ampere
    =Ohm
    ~None of the above
}

If one resistor is removed from a parallel circuit, the total resistance _____. {
    =increases
    ~decreases
    ~remains the same
    ~None of the above
}

In a parallel circuit, total current is the _____ of the individual branch currents. {
    =sum
    ~difference
    ~product
    ~None of the above
}

The parallel combination of resistors is used in _____. {
    =household wiring
    ~electric motors
    ~transformers
}

If two 5Ω resistors are connected in parallel, the equivalent resistance is _____. {
    =2.5Ω
    ~10Ω
    ~5Ω
    ~None of the above
}

//Numericals

Two resistors of 4Ω and 6Ω are connected in parallel. Find the equivalent resistance. {
    =2.4Ω
    ~3Ω
    ~4Ω
    ~10Ω
}

Three resistors of 3Ω, 6Ω, and 9Ω are connected in parallel. Find the total resistance. {
    =1.64Ω
    ~2Ω
    ~3Ω
    ~4Ω
}

Two resistors of 6Ω and 12Ω are connected in parallel. What is the equivalent resistance? {
    =4Ω
    ~6Ω
    ~8Ω
    ~9Ω
}

Three resistors of 3Ω, 6Ω, and 9Ω are connected in parallel. Find the equivalent resistance. {
    =1.64Ω
    ~2Ω
    ~3Ω
    ~4Ω
}

Two resistors of 10Ω and 20Ω are connected in parallel. Find the equivalent resistance. {
    ~5Ω
    =6.67Ω
    ~10Ω
    ~15Ω
}

//Match the following

Match the following items from Column A with their correct corresponding options from Column B\:
{
=Parallel Circuit -> Voltage is same
=Adding more resistors -> Decreases resistance
=Household wiring -> Uses Parallel Circuits
=Total current -> Sum of branch currents
}


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