The study of large distances and large sizes are known as
Answers
Explanation:
11th
Physics
Units and Measurement
Measurement of Length
Explain the parallax method...
PHYSICS
Explain the parallax method for measuring large distances. With the help of it, explain the method to determine the shape of a heavenly body.
MEDIUM
ANSWER
Measurement of Large Distances
Length: It is defined as the difference between two positions taken by two events that occur instantly.
(i) Parallax Method: When an object is seen by closing our right and left eye alternatively, there is a shift in the position of the object w.r.t. the background observed. This is known as parallax.
Imagine an object P placed at a distance x from our eyes. Let the line joining the object to left and right eye make O angle w.r.t. each other. O is called parallax angle.
The distance LR is called basis.
θ=
Radius
LengthofArc
(ii) Size of Astronomical Object: Diameter of Moon: Let Moon be the astronomical object whose diameter is to he measured. We observed Moon with the help of a telescope. Let it be observed from a place F on Earth and make an angle 0 with the two ends P and Q of moon and the point K, as shown in fig. 1.5. 0 is called the angular diameter of the Moon.
Lt d be the distance of the Moon from the Earth.
Then,angular diameter,θ=
d
PQ
=
radius
Lengthofthearc
(iii) Reflection or Echo Method: A gun is fired towards the hill and the time taken between instant of firing and hearing of echo bet. In this time interval, sound first travels towards the hill from the place of firing and then hack from the hill to the place of firing. Lt u be the speed of sound. x be the distance of hill from the place of firing the gun, then.
Answer:
Parallax Method is the study of large distance and larde sizes