JEE Main 2020 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 8 January 2020, Shift 1, Physics Q20

Question 20 of 75 in this shift, Physics question 20 of 25, Section A.

The length of a potentiometer wire is 1200 cm and it carries a current of 60 mA. For a cell of emf 5 V and internal resistance of 20

\Omega

, the null point on it is found to be at 1000 cm. The resistance of whole wire is :

(1)60 $\Omega$
(2)80 $\Omega$
(3)100 $\Omega$ Official answer
(4)120 $\Omega$

Official answer

Option 3

NTA final key (Jan 2020).

Chapter: Current Electricity
Topic: Potentiometer
Idea tested: Potential Gradient Calculation

Same idea in other shifts

Asked 5× in all

26 Jul 2022, Shift 2 · Q59A potentiometer wire of length 300 cm is connected in series with a resistance 780 $\Omega$ and a standard cell of emf 4V. A constant…MediumNumerical value
28 Jul 2022, Shift 1 · Q55As shown in the figure, a potentiometer wire of resistance 20 $\Omega$ and length 300 cm is connected with resistance box (R.B.) and a…HardNumerical valueHas a figure
24 Jun 2022, Shift 2 · Q53A potentiometer wire of length 10 m and resistance 20 $\Omega$ is connected in series with a 25 V battery and an external resistance 30…MediumNumerical value
2 Sep 2020, Shift 2 · Q20A potentiometer wire PQ of 1 m length is connected to a standard cell E $_1$ . Another cell E $_2$ of emf 1.02 V is connected with a…EasyDiagram basedHas 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.