Learn

Saturday, 31 October

JEE Main · Physics · Waves

Moving Source Cases

JEE Main asked Moving Source Cases 3 times in 3 of the 108 shifts Lumi analysed, in 2022 and 2023. It belongs to Doppler Effect, in Waves (Physics). The longest wait between two years asking it was 1 year. In 2023 it came in more than one shift of the same year.

Updated 2026-10-24

Times asked
3
in 3 shifts
Years
2 of 8
First asked
2022
last in 2023
Pattern
Occasional
across the analysed shifts

Questions on this idea a shift, by year

2017–2026. Asked in 2022 and 2023. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Physics questions.

00.10.20’170’200’210.03’220.14’230’240’250’26

Raw count: 2017: 0 in 1 shift · 2020: 0 in 12 shifts · 2021: 0 in 24 shifts · 2022: 1 in 24 shifts · 2023: 2 in 12 shifts · 2024: 0 in 18 shifts · 2025: 0 in 8 shifts · 2026: 0 in 9 shifts.

Shift by shift

Each square is one analysed shift, in date order. Open a filled one for that paper.

  • 20260 of 9
  • 20250 of 8
  • 20240 of 18
  • 20232 of 12
  • 20221 of 24
  • 20210 of 24
  • 20200 of 12
  • 20170 of 1

Asked in that shift More than once Not asked

How JEE Main framed it

Single correct is the usual form. Skill tested: calculation.

  • Doppler with observer moving along with source
  • Frequency heard with both source and observer moving

Difficulty

Easy 1Medium 2Hard 0

1 of the 3 questions had a numerical answer.

Every question

All 3 questions

From the official JEE Main shift papers, newest first. Open one for the full question, the options and the official answer.

  1. 11 Apr 2023, Shift 2 · Q31A car P travelling at 20 ms−120\ \mathrm{ms^{-1}} sounds its horn at a frequency of 400 Hz400\ \mathrm{Hz}. Another car Q is travelling behind the…MediumSingle correct
  2. 8 Apr 2023, Shift 1 · Q31The engine of a train moving with speed 10 ms−110\ \mathrm{ms^{-1}} towards a platform sounds a whistle at frequency 400 Hz400\ \mathrm{Hz}. The…EasySingle correct
  3. 26 Jul 2022, Shift 1 · Q54When a car is approaching the observer, the frequency of horn is 100 Hz. After passing the observer, it is 50 Hz. If the observer moves…MediumNumerical value

Shifts: 26 Jul 2022, Shift 1, 8 Apr 2023, Shift 1, 11 Apr 2023, Shift 2.

Same topic

Other ideas in Doppler Effect

Doppler Effect has 8 ideas JEE Main has asked; 5 of them came up in more than one question.

Topic analysisChapter analysisStudy this chapterAll repeated ideas