Questions

The first step in the refining of petroleum is distillation i.e,  the fractionation of crude oil in atmospheric and vacuum distillation towers.

The first process petroleum refinery is known as distillation. In this process, crude oil is heated and fed into a distillation column. As the temperature of the crude oil in the distillation column rises, the crude oil separates itself into different components, called "fractions." The fractions are then captured separately. Each fraction corresponds to a different type of petroleum product, depending on the temperature at which that fraction boils off the crude oil mixture.

Let the required number be 'N'

given that its quarter i.e; N/4 exceeds its double i.e, 2N by 7

=> N/4 + 7 = 2N

=> N + 28 = 8N

7N = 28

N = 4.

A team of scientists led by Abhay Mudholkar, from CSIR-National Institute of Oceanography (CSIR-NIO) in Goa on February 17, 2017 informed that India’s only live volcano, the barren island volcano in the Andaman and Nicobar Islands has started erupting smoke and lava again. The Barren Island volcano last erupted in 1991 after lying dormant for 150 years. Again the volcano has started showing sporadic activity in small intervals of 5-10 minutes. As per the scientists, during the day only ash clouds were observed, but after sunset red lava foundations were erupting from the crater into the atmosphere and hot lava streamed down the slopes.