Answer
Verified
396k+ views
Hint: Here we will use the relation between power, voltage and resistance to determine the resistance of an individual bulb. Power is given as the ratio of square of the voltage limit of the bulb to the resistance. Then we will find the equivalent resistance of the bulb when it is connected in series connection and parallel connection and use the same relation between power, voltage and resistance to determine the power in each combination of bulbs. We need to use the source voltage and equivalent resistance in this case.
Formula used:
\[P=\dfrac{{{V}^{2}}}{R}\]
Complete step by step answer:
Firstly, we will find the resistance offered by a single bulb by using the voltage limit and power limit of the bulb which are given as \[220V\] and \[100W\] respectively. The resistance of a single bulb will be,
\[R=\dfrac{{{V}^{2}}}{P}=\dfrac{{{\left( 220 \right)}^{2}}}{100}=484\Omega \]
Now, if we connect two of these bulbs in a series connection, the equivalent resistance will be,
\[{{R}_{\text{equivalent}}}=R+R=2R=2\times 484=968\Omega \]
So, we have the equivalent resistance when the bulbs are connected in series. Now, to determine the power when connected to a \[220V\] source, we will use the expression,
\[P=\dfrac{{{V}^{2}}}{{{R}_{\text{equivalent}}}}=\dfrac{{{\left( 220 \right)}^{2}}}{968}=50W\]
So, the power drawn by the series combination of these bulbs is \[50W\].
Now, if we connect these two bulbs in parallel connection, the equivalent resistance will be,
\[\begin{align}
& \dfrac{1}{{{R}_{\text{equivalent}}}}=\dfrac{1}{R}+\dfrac{1}{R}=\dfrac{2}{R}=\dfrac{2}{484}=\dfrac{1}{242} \\
& \Rightarrow {{R}_{\text{equivalent}}}=242\Omega \\
\end{align}\]
So, we have equivalent resistance when the given bulbs are connected in parallel. Now, the power drawn while connecting these bulbs in parallel is,
\[P=\dfrac{{{V}^{2}}}{{{R}_{\text{equivalent}}}}=\dfrac{{{\left( 220 \right)}^{2}}}{242}=100W\]
So, the power drawn by the parallel combination of these bulbs is \[100W\].
Therefore, we can conclude that the power drawn when two of the given bulbs are connected in series combination is \[50W\] and in parallel combination is \[100W\].
So, option a is the correct answer.
Note:
We can also solve this question by using the relation between power, current and resistance which is given as \[P={{I}^{2}}R\]. But instead of using the given voltage supply directly, we will need to find the current passing through the circuit by using ohm's law. While finding this current we must remember to use the equivalent resistance for series and parallel combinations.
Formula used:
\[P=\dfrac{{{V}^{2}}}{R}\]
Complete step by step answer:
Firstly, we will find the resistance offered by a single bulb by using the voltage limit and power limit of the bulb which are given as \[220V\] and \[100W\] respectively. The resistance of a single bulb will be,
\[R=\dfrac{{{V}^{2}}}{P}=\dfrac{{{\left( 220 \right)}^{2}}}{100}=484\Omega \]
Now, if we connect two of these bulbs in a series connection, the equivalent resistance will be,
\[{{R}_{\text{equivalent}}}=R+R=2R=2\times 484=968\Omega \]
So, we have the equivalent resistance when the bulbs are connected in series. Now, to determine the power when connected to a \[220V\] source, we will use the expression,
\[P=\dfrac{{{V}^{2}}}{{{R}_{\text{equivalent}}}}=\dfrac{{{\left( 220 \right)}^{2}}}{968}=50W\]
So, the power drawn by the series combination of these bulbs is \[50W\].
Now, if we connect these two bulbs in parallel connection, the equivalent resistance will be,
\[\begin{align}
& \dfrac{1}{{{R}_{\text{equivalent}}}}=\dfrac{1}{R}+\dfrac{1}{R}=\dfrac{2}{R}=\dfrac{2}{484}=\dfrac{1}{242} \\
& \Rightarrow {{R}_{\text{equivalent}}}=242\Omega \\
\end{align}\]
So, we have equivalent resistance when the given bulbs are connected in parallel. Now, the power drawn while connecting these bulbs in parallel is,
\[P=\dfrac{{{V}^{2}}}{{{R}_{\text{equivalent}}}}=\dfrac{{{\left( 220 \right)}^{2}}}{242}=100W\]
So, the power drawn by the parallel combination of these bulbs is \[100W\].
Therefore, we can conclude that the power drawn when two of the given bulbs are connected in series combination is \[50W\] and in parallel combination is \[100W\].
So, option a is the correct answer.
Note:
We can also solve this question by using the relation between power, current and resistance which is given as \[P={{I}^{2}}R\]. But instead of using the given voltage supply directly, we will need to find the current passing through the circuit by using ohm's law. While finding this current we must remember to use the equivalent resistance for series and parallel combinations.
Recently Updated Pages
Basicity of sulphurous acid and sulphuric acid are
Assertion The resistivity of a semiconductor increases class 13 physics CBSE
Three beakers labelled as A B and C each containing 25 mL of water were taken A small amount of NaOH anhydrous CuSO4 and NaCl were added to the beakers A B and C respectively It was observed that there was an increase in the temperature of the solutions contained in beakers A and B whereas in case of beaker C the temperature of the solution falls Which one of the following statements isarecorrect i In beakers A and B exothermic process has occurred ii In beakers A and B endothermic process has occurred iii In beaker C exothermic process has occurred iv In beaker C endothermic process has occurred
The branch of science which deals with nature and natural class 10 physics CBSE
What is the stopping potential when the metal with class 12 physics JEE_Main
The momentum of a photon is 2 times 10 16gm cmsec Its class 12 physics JEE_Main
Trending doubts
Difference between Prokaryotic cell and Eukaryotic class 11 biology CBSE
Fill the blanks with the suitable prepositions 1 The class 9 english CBSE
Write an application to the principal requesting five class 10 english CBSE
Difference Between Plant Cell and Animal Cell
a Tabulate the differences in the characteristics of class 12 chemistry CBSE
Change the following sentences into negative and interrogative class 10 english CBSE
What organs are located on the left side of your body class 11 biology CBSE
Discuss what these phrases mean to you A a yellow wood class 9 english CBSE
List some examples of Rabi and Kharif crops class 8 biology CBSE