Three resistors \(2\Omega ,4\Omega \) and \(5\Omega \) are combined in parallel. What is the total resistance of the combination?
Answer
Total resistance,\(R=\frac{20}{19}\;\Omega\)
To Keep Reading This Answer, Download the App
4.6
Review from Google Play
To Keep Reading This Answer, Download the App
4.6
Review from Google Play
Solution
Given: \({{R}}_{1}=2\;\Omega\) \(\mathit{R}_2=4\;\Omega\) \(\mathit{R}_3=5\;\Omega\) When the resistors are in parallel, \(\frac{1}{R}=\frac{1}{{R}_{1}}+\frac{1}{{R}_{2}}+\frac{1}{{R}_{3}}\) \(\frac{1}{R}=\frac12+\frac 1 4+\frac 1 5\) \(\frac{1}{R}=\frac{10+5+4}{20}\) \(\frac{1}{R}=\frac{19}{20}\) Total resistance,\(R=\frac{20}{19}\;\Omega\)
At room temperature \({(27.0 {\degree}C)}\) the resistance of a heating element is \(\text{100 $\Omega $.}\) What is the temperature of the element if the resistance is found to be \(\text{17 $\Omega $,}\) given that the temperature coefficient of the material of the resistor is \({1.70 {\times} 10^{-4} {\degree}C}.\)
In a metre bridge \([\)figure shown below\(],\) the balance point is found to be at \(39.5\) cm from the end \(A\) , when the resistor \(Y\) is of \(12.5\;\Omega \) . Determine the resistance of \(X\) . Why are theconnections between resistors in a Wheatstone or meter bridge made of thick copper strips?
In a metre bridge \([\)figure shown below\(]\), the balance point is found to be at \(39.5 \;\text{cm}\) from the end \(A\) , when the resistor \(Y\) is of \(12.5\;\Omega \) . Determine the resistance of \(X\) .Determine the balance point of the bridge shown below if \(X\) and \(Y\) are interchanged.
\(10\) mL of \(1\) mM surfactant solution forms a monolayer covering \(0.24cm^{2}\) on a polar substrate. If the polar head is approximated as a cube, what is its edge length?( )
A molecule of a substance has a permanent electric dipole moment of magnitude \(10^{-29}\mathit{Cm}\) . A mole of this substance is polarised \((\) at low temperature \()\) by applying a strong electrostatic field of magnitude \(10^6Vm^{-1}\) . The direction of the field is suddenly changed by an angle of \(60^{{\circ}}\) . Estimate the heat released by the substance in aligning its dipoles along the new direction of the field. For simplicity. assume \(100\) polarisation of the sample.
A storage battery of emf \(\text{8.0 V}\) and internal resistance \(\text{0.5 $\Omega $}\) is being charged by a \(\text{120 }\mathit{V}\) dc supply using a series resistor of \(\text{15.5 $\Omega $.}\) What is the terminal voltage of the battery during charging? What is the purpose of having a series resistor in the charging circuit?
In a potentiometer arrangement, a cell of emf \(1.25\; \text{V}\) gives a balance point at \(35.0\text{ cm}\) length of the wire. If the cell is replaced by another cell and the balance point shifts to \(63.0\text{ cm}\) , what is the emf of the second cell?