MPSC 2021 PYQ — Attempt 100 Previous Year Questions

MPSC 2021 PYQ 1 — Quantitative Aptitude

The Spectrum of Light The light is kind of electromagnetic spectrum. Radio waves are electromagnetic in nature. Any electromagnetic wave is made up of electric and magnetic fields that travel through space from one place to another. The basic characteristics of the electromagnetic radiation are its frequency and wavelength. To put light waves into perspective with lower radio and other frequencies. The left end of the spectrum is very low frequency electrical signals such as AC power 50 Hz and audio or sound frequencies in 20 Hz to 20 kHz range. These are the lower frequencies that have long wavelengths. Higher up frequency scale to right is wide range of radio frequencies. Radio frequencies range from 10 kHz to 300 GHz. Microwaves extends from 1 to 300 GHz. Even further up the scale we find visible light. The frequency of Optical spectrum is in the range of 3 x 101! to 3 x 101° Hz. This includes infrared and ultraviolet as well as visible parts of the spectrum. The visible spectrum is 4.3 x 104 to 7.5 x 1014 Hz. But we are rarely referred to the frequency of light. Instead we state light in a distance measured in terms of the meters between peaks of wave. Light waves are very short and are usually expressed in Nanometers or microns (one millionth of a meter). Visible light is in the range of 400 to 700 nanometers (nm) or 0.4 to 0.7 micrometers (jm) depending upon colour of light. Short wavelength light is violet and long wavelength light is red colour respectively. Right below the visible light is region of infrared rays cannot be seen. The source of most infrared is heat. Right above visible spectrum is ultraviolet range. Infrared and ultraviolet are included in what we call as optical spectrum. Beyond that are x-rays, gamma rays and cosmic rays. Light travels in a straight line. Light rays emitted by a candle or a light bulb, move out in the straight line in all directions. Light travels at the speed of 300,000,000 meter/second. i.e. 1,86,000 miles/s. The speed of the light depends upon the medium through which light passes. The above speed of light is in the free space means light travelling in air or vacuum. When light travels through glass medium its speed lowers. Light can be manipulated in many ways. Lenses are widely used to focus, enlarge or to decrease the size of the light waves from same source. Lenses permit useful devices such as cameras, binoculars, microscopes, and telescopes. Reflection and refraction are the important characteristics of light. The law of reflection state that angle of reflection is equal to angle of incidence. Refraction is another characteristic of light states that it’s bending of the light when light rays passes through one medium to another. There is relation between wavelength, frequency and speed of the light. Wavelength is inversely proportional to frequency. Unit of the light is generally expressed in terms of nanometers or micrometers.

Speed of light is.

1. 3x10^8 m/s
2. 3x10^8 cm/s
3. 3x10^8 km/s
4. 3x10^8 inch/s

Answer: A. 3x10^8 m/s

MPSC 2021 PYQ 2 — Science

Which has maximum Ionization Energy ?

1. Mg
2. Mg+
3. Mg2+
4. All of the above

Answer: C. Mg2+

MPSC 2021 PYQ 3 — Reasoning

Later half of the twentieth century witnessed emergence of new trends in Archaeology. New discoveries in physical sciences and their application in archaeology resulted in an inclination towards sciences. American archaeologist Lewis Binford pioneered the use of the methodology of Scientific Philosophy in archaeological research. While in England, David Clarke proved that the New Archaeological method of using concepts from disciplines such as anthropology, geography and environmental sciences in furnishing archaeological evidences can extract much more information. New Archeology can be termed as scientific archeology. The main aim of the old school archeologists was to establish the chronology of human culture with the help of excavations. New archeology considers this a mistake; as archeology is not just about chronology. It considers that it is the duty of the archeologists to delve deep so as to establish with reliable evidence, the cause and effect relationship behind every historical event. A simple example of this can be the report of the Mohenjodaro excavation. There were seven successive layers of habitation before the Indus civilisation. Finally perished. It was believed that the Aryans invaded India and destroyed the Indus civilisation under the leadership of Indra, their chief deity. This was a Rigvedic evidence of literary nature and how could it be completely relied upon? There is no physical evidence of the Aryan invasion. It can be seen that the Indus civilisation died away because of climatic changes. Scientific evidences conclusively proving this have been found. New Archeology focuses on the relationship between cause and effects. New Archeology has recently invited some criticism. Professor Ian Hodder from the Cambridge University is a major critic. According to him, it is not enough to defend only on scientific evidences for an explanation of cultural changes, but the context of excavated remains is very important for their proper interpretation, This ideology, has therefore been called as Contextual Archeology. Now some Archeologists have moved ahead of this ideology. Socio-economic conditions of man have always been studied, and now a study of the mentalities of ancient humans is gaining momentum. How did religion and philosophy merge, what were the thoughts in the minds of the ancient painters - such and other things are being studied. Archeology in the twenty-first century is indeed going to be very different.

Choose the correct option after carefully reading the sentences: (a) It is unscientific to believe only the literary evidence from the Rigveda. (b)There is no material evidence available of Aryan Invasion. (c)There are evidences proving the Indus Civilisation ended aa a result of climatic changes.

1. (a), (b) and (c) all are correct.
2. (a) and (b) are correct and (c) is their result.
3. (a) and (b) are incorrect and (c) is correct.
4. (a), (b) and (c) all are incorrect.

Answer: B. (a) and (b) are correct and (c) is their result.