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Saturday, 31 October

JEE Main 2024 · MathsMultiple choiceSingle correctEasyApplication

JEE Main 31 January 2024, Shift 2, Maths Q13

Question 13 of 90 in this shift, Maths question 13 of 30, Section A.

The temperature T(t)T(t) of a body at time t=0t=0 is 160∘160^\circ F and it decreases continuously as per the differential equation dTdt=−K(T−80)\frac{dT}{dt}=-K(T-80), where KK is a positive constant. If T(15)=120∘T(15)=120^\circF, then T(45)T(45) is equal to
  1. (1)80∘80^\circ F
  2. (2)85∘85^\circ F
  3. (3)90∘90^\circ FOfficial answer
  4. (4)95∘95^\circ F

Official answer

Option 3

NTA final key.

Chapter
Differential Equations
Topic
Variable Separable Form
Idea tested
Physical Modeling Applications

Same idea in other shifts

Asked 2× in all
  1. 24 Feb 2021, Shift 1 · Q72The population P=P(t)P = P(t) at time 't' of a certain species follows the differential equation dPdt=0.5P−450\frac{dP}{dt} = 0.5P - 450. If…MediumSingle correct

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.