Gce Model Questions Vol1 2021 Physics Question 24
Practice objective / multiple choice question 24 from the 2021 Gce Model Questions Vol1 Physics examination.
A 12 V DC supply powers two resistors \(R_1\) and \(R_2\) connected in parallel. At \(20^{\circ}\text{C}\) their resistances are \(R_{1,0}=10\;\Omega\) and \(R_{2,0}=20\;\Omega\) with temperature coefficients \(\alpha_1 = 4.0\times10^{-3}\;^{\circ}\text{C}^{-1}\) and \(\alpha_2 = 1.5\times10^{-3}\;^{\circ}\text{C}^{-1}\) respectively. Both resistors heat uniformly to a common temperature \(T\) (in °C) so that their resistances become \(R_1 = R_{1,0}[1+\alpha_1(T-20)]\) and \(R_2 = R_{2,0}[1+\alpha_2(T-20)]\). Find the temperature \(T\) at which the power dissipated in \(R_1\) equals the power dissipated in \(R_2\). Then calculate the total current drawn from the supply at that temperature.
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About This Question
This is Gce Model Questions Vol1 2021 Physics Question 24. It is one of the objective questions from the 2021 Gce Model Questions Vol1 Physics examination.
Difficulty level: Hard .
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