Questions

Given two trains of length = 180 mts + 180 mts 

The distance is = Length of trains = 360 mts 

Speed = 58 - 50 = 8 kmph x 5/18 m/s

Then, Time = dis/speed = (360x18) / (8x5) = 162 sec.

ROM cannot be used as stack because it is not possible to write to ROM.

Allotropes are the different physical forms of an element. Here in the given options, diamond and graphite are the pair of allotropes of carbon.

Some more examples are Molecular oxygen and ozone are pair of allotropes, Black and red phosphorous are also pairs of allotropes.

India's first passenger train run took place from Mumbai to Thane for around 34 kms on 16th April in the year 1853. 

That train was hauled by three steam locomotives : Sahib, Sindh and Sultan.

That train had 14 carriages, carrying around 400 passengers.