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Saturday, 31 October

JEE Main 2020 · PhysicsMultiple choiceSingle correctMediumRecall

JEE Main 2 September 2020, Shift 1, Physics Q12

Question 12 of 75 in this shift, Physics question 12 of 25.

Consider four conducting materials copper, tungsten, mercury and aluminium with resistivity ρC\rho_C, ρT\rho_T, ρM\rho_M and ρA\rho_A respectively. Then :
  1. (1)ρC>ρA>ρT\rho_C>\rho_A>\rho_T
  2. (2)ρA>ρT>ρC\rho_A>\rho_T>\rho_C
  3. (3)ρA>ρM>ρC\rho_A>\rho_M>\rho_C
  4. (4)ρM>ρA>ρC\rho_M>\rho_A>\rho_COfficial answer

Official answer

Option 4

NTA final key (Sep 2020).

Same idea in other shifts

Asked 10× in all
  1. 6 Apr 2023, Shift 1 · Q55The length of a metallic wire is increased by 20% and its area of cross section is reduced by 4%. The percentage change in resistance of…EasyNumerical value
  2. 10 Apr 2023, Shift 2 · Q60A rectangular parallelopiped is measured as 1 cm ×\times 1 cm ×\times 100 cm. If its specific resistance is 3×10−7 Ω3\times10^{-7}\ \Omega m,…EasyNumerical value
  3. 25 Jul 2022, Shift 1 · Q58Eight copper wire of length ll and diameter dd are joined in parallel to form a single composite conductor of resistance RR. If a…EasyNumerical value
  4. 29 Jul 2022, Shift 1 · Q42Two metallic wires of identical dimensions are connected in series. If σ1\sigma_1 and σ2\sigma_2 are the conductivities of the these wires…MediumSingle correct
  5. 30 Jun 2022, Shift 1 · Q45An electric cable of copper has just one wire of radius 9 mm. Its resistance is 14 Ω\Omega. If this single copper wire of the cable is…EasySingle correct
  6. 4 Aug 2021, Shift 1 · Q21A wire of length L is coated by another conducting material of double resistivity and the thickness of the layer is equal to the radius of…MediumNumerical valueHas a figure
  7. 26 Aug 2021, Shift 1 · Q17What equal length of an iron wire and a copper-nickel alloy wire, each of 2 mm diameter connected parallel to give an equivalent…MediumSingle correct
  8. 22 Jul 2021, Shift 2 · Q7A Copper (Cu) rod of length 25 cm and cross-sectional area 3 mm2^2 is joined with a similar Aluminium (Al) rod as shown in figure. Find…EasySingle correctHas a figure

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.