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Saturday, 31 October

JEE Main 2020 · PhysicsMultiple choiceDiagram basedMediumMulti-step

JEE Main 5 September 2020, Shift 1, Physics Q2

Question 2 of 75 in this shift, Physics question 2 of 25.

A balloon is moving up in air vertically above a point A on the ground. When it is at a height h1h_1, a girl standing at a distance d (point B) from A (see figure) sees it at an angle 45° with respect to the vertical. When the balloon climbs up a further height h2h_2, it is seen at an angle 60° with respect to the vertical if the girl moves further by a distance 2.464 d (point C). Then the height h2h_2 is (given tan30° = 0.5774) :

The figure, in words

Vertical line through A going up, with heights h_1 (A up to the lower marked point) and h_2 (further up to the upper marked point) marked by arrows. Horizontal line along the ground with points A, B, C; distance A to B marked d and B to C marked 2.464 d. A line from the lower point on the vertical to B makes angle 45° (marked near B); a line from the upper point to C makes angle 60° (marked near C).
  1. (1)1.464 d
  2. (2)0.732 d
  3. (3)0.464 d
  4. (4)dOfficial answer

Official answer

Option 4

NTA final key (Sep 2020).

Chapter
Motion in a Straight Line
Topic
No close match in our taxonomy
Idea tested
No close match in our taxonomy

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. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.