COMEDK · Physics · 19. Current Electricity
Wires made of iron and silicon are cooled from \(50^{\circ} \mathrm{C}\) to \(30^{\circ} \mathrm{C}\), then
- A resistance of both wires decreases
- B resistance of both wires increases
- C resistance of iron increases and that of silicon decreases
- D resistance of iron decreases and that of silicon increases
Answer & Solution
Correct Answer
(D) resistance of iron decreases and that of silicon increases
Step-by-step Solution
Detailed explanation
The conductors have positive temperature coefficient, while semiconductors have negative temperature coefficient. So, when iron and silicon wires are cooled from \(50^{\circ} \mathrm{C}\) to \(30^{\circ} \mathrm{C}\), the resistance of iron decreases, while that of silicon…
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- Which one of the following is not a tunit of Young's modulus?COMEDK 2017 Easy
- A small metallic sphere carrying a charge \(2 \times 10^{-6} C\) is suspended using a thin thread of negligible mass from a rigid support, in a horizontal electric filed \(5 \times 10^4 \mathrm{Vm}^{-1}\). If the thread is making an angle \(30^0\) with the vertical, What is the tension in the thread?COMEDK 2025 Medium
- A small current carrying loop of area \(A\) behaves like a tiny magnet of magnetic moment \(M\). Current in the loop isCOMEDK 2016 Easy
- \(0.04 \mathrm{~m}\) of glass contains the same number of waves as \(0.05 \mathrm{~m}\) of water, when monochromatic light passes through them normally. Refractive index of water is \(4 / 3\). Refractive index of glass isCOMEDK 2016 Hard
- In the normal adjustment of an astronomical telescope, the objective and eyepiece are 36 cm apart. If the magnifying power of the telescope is 8, find the focal lengths of the objective and eyepiece.COMEDK 2025 Medium
- For an ideal gas, coefficient of volume expansion is given byCOMEDK 2021 Medium
More PYQs from COMEDK
- \(\text { If } x^2+y^2=t+\dfrac{1}{t} \text { and } x^4+y^4=t^2+\dfrac{1}{t^2} \text { then } \dfrac{d y}{d x}=\)COMEDK 2024 Medium
- The behaviour of real gas approaches ideal behaviour atCOMEDK 2023 Easy
- The maximum value of \(P=500 x+400 y\) for the given constraints \(x+y \leq 200, \quad x \geq 20, \quad y \geq 4 x, \quad y \geq 0\) isCOMEDK 2024 Medium
- The coefficient of \(x^{29}\) in the expansion of \(\left(1-3 x+3 x^2-x^3\right)^{15}\) isCOMEDK 2023 Medium
- Waxes are esters ofCOMEDK 2017 Medium
- If \(A=\left[\begin{array}{rr}\cos \dfrac{2 \pi}{3} & -\sin \dfrac{2 \pi}{3} \\ \sin \dfrac{2 \pi}{3} & \cos \dfrac{2 \pi}{3}\end{array}\right]\) and I is an identity matrix of order \(2 \times 2\) then \(A^3=\)COMEDK 2025 Medium