Explanations:Jantar Mantar is a significant historical and astronomical observatory located in Jaipur, Rajasthan, India. It was constructed by Maharaja Jai Singh II of Jaipur in the early 18th century, specifically between 1724 and 1734. The observatory is a collection of architectural instruments designed to measure time, predict eclipses, and track the movement of celestial bodies. Jai Singh II was a keen astronomer and mathematician who built several such observatories across India, including in Delhi, Ujjain, Mathura, and Varanasi.
The name "Jantar Mantar" is derived from the Sanskrit words "Yantra" (instruments) and "Mantra" (formulae). The observatory in Jaipur is the largest and most well-preserved of the five built by Jai Singh II. It consists of 19 major geometric devices for measuring time, predicting eclipses, tracking the stars' location as the earth orbits around the sun, ascertaining the declinations of planets, and determining the celestial altitudes and related ephemerides.
Understanding the historical context and the contributions of Maharaja Jai Singh II is crucial for comprehending the significance of Jantar Mantar. Jai Singh II was a Rajput ruler who was deeply interested in astronomy and mathematics. He was influenced by the works of Islamic and European astronomers and sought to create observatories that would help in the accurate prediction of celestial events. His efforts led to the construction of these observatories, which are now recognized as important historical and scientific landmarks.
It is important to note that while there were many rulers in Rajasthan during the period, only Maharaja Jai Singh II of Jaipur is associated with the construction of Jantar Mantar. The other options provided in the question are either incorrect rulers or incorrect locations, which can lead to confusion. Therefore, the correct answer is that Jantar Mantar was built by Maharaja Jai Singh 2 of Jaipur.