JEE Main 2022 · ChemistryNumerical answerNumerical valueMediumCalculation

JEE Main 28 June 2022, Shift 2, Chemistry Q85

Question 85 of 90 in this shift, Chemistry question 25 of 30, Section B.

A radioactive element has a half life of 200 days. The percentage of original activity remaining after 83 days is __________ . (Nearest integer) (Given : antilog 0.125 =1.333, antilog 0.693 =4.93)

Official answer

NTA final key.

Chapter: Chemical Kinetics
Topic: Integrated Rate Equations
Idea tested: First Order Half-Life

Same idea in other shifts

Asked 6× in all

1 Feb 2024, Shift 1 · Q86The ratio of $\frac{^{14}\mathrm{C}}{^{12}\mathrm{C}}$ in a piece of wood is $\frac{1}{8}$ part that of atmosphere. If half life of…EasyNumerical value
13 Apr 2023, Shift 1 · Q87 $t_{87.5}$ is the time required for the reaction to undergo 87.5% completion and $t_{50}$ is the time required for the reaction to undergo…EasyNumerical value
25 Jul 2022, Shift 2 · Q85For the decomposition of azomethane, $\mathrm{CH_3N_2CH_3(g) \rightarrow CH_3CH_3(g) + N_2(g)}$ , a first order reaction, the variation in…MediumNumerical valueHas a figure
27 Jul 2022, Shift 2 · Q85[A] $\rightarrow$ [B] Reactant Product If formation of compound [B] follows the first order of kinetics and after 70 minutes the…EasyNumerical value
26 Jun 2022, Shift 1 · Q84A flask is filled with equal moles of A and B. The half lives of A and B are 100 s and 50 s respectively and are independent of the…HardNumerical value

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.