Satellites used for telecommunication relay are kept in a geostationary orbit. A satellite is said to be in such an orbit when: 1. The orbit is geosynchronous. 2. The orbit is circular. 3. The orbit lies in the plane of the Earth's equator. 4. The orbit is at an altitude of 22,236 km. Select the correct answer using the codes given below:

Which of the following pairs is/are correctly matched? Spacecraft and Purpose

In the context of modern scientific research, consider the following statements about IceCube', a particle detector located at South Pole, which was recently in the news: 1. It is the world's largest neutrino detector, encompassing a cubic kilometre of ice. 2. It is a powerful telescope to search for dark matter. 3. It is buried deep in the ice.

In which of the following activities are Indian Remote Sensing (IRS) satellites used? 1. Assessment of crop productivity 2. Locating groundwater resources 3. Mineral exploration 4. Telecommunications 5. Traffic studies. Select the correct answer using the code given below.