L3 – Parallax Method Units and Measurements


Friday, February 05, 2021

Agam Sir

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Topics/Questions discussed in this video:

Example 2.2 A man wishes to estimate the distance of a nearby tower from him. He stands at a point A in front of the tower C and spots a very distant object O in line with AC. He then walks perpendicular to AC up to B, a distance of 100 m, and looks at O and C again. Since O is very distant, the direction BO  is practically the same as AO; but he finds the line of sight of C shifted from the original line of sight by an angle θ = 400 (θ is known as ‘parallax’) estimate the distance of the tower C from his original position A.

Example 2.3 The moon is observed from two diametrically opposite points A and B on Earth. The angle θ subtended at the moon by the two directions of observation is 1o54′ . Given the diameter of the Earth to be about 1.276 ×107 m, compute the
distance of the moon from the Earth.

Example 2.4 The Sun’s angular diameter is measured to be 1920′′. The distance D of the Sun from the Earth is 1.496 × 1011 m. What is the diameter of the Sun ?

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Agam Sir

Agam Sir


Ashish Kumar a.k.a Agam Sir has vast experience of 12+ years of teaching Mathematics and Physics. He has skills (academic and vocational) that go with working alongside people, especially young people, their parent(s) and the institutes that works with him. He always seek to be an agent of positive change and progression, a mentor/ trainer/ educator for learners/students, seeing that their needs are ideally met.