EASY
Earn 100

What is the most difficult in physics?

Important Questions on Physical World and Measurement

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A carrot looks orange in colour because of the β carotene molecule in it. This means that the β carotene molecule absorbs light of wavelengths,
HARD
A particle of mass 200 MeV c-2 collides with a hydrogen atom at rest. Soon after the collision, the particle comes to rest, and the atom recoils and goes to its first excited state. The initial kinetic energy of the particle (in eV) is N4. The value of N is: (Given the mass of the hydrogen atom to be 1 GeV c-2).........
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A total solar eclipse is observed from the earth. At the same time an observer on the moon views the earth. She is most likely to see (E denotes the earth)

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Name the scientist and the country of his origin whose field of work was ‘Cosmic Rays'.
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Some of the most profound statements on the nature of science have come from Albert Einstein, one of the greatest scientists of all time. What do you think did Einstein mean when he said: “The most incomprehensible thing about the world is that it is comprehensible”.
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Which one of the following statements is true about the ‘laws’ and ‘theories’ in science?

MEDIUM

Which scientific instrument is used to record the speed of an aircraft?

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“Every great physical theory starts as a heresy and ends as a dogma". Give some examples from the history of science of the validity of this incisive remark.
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A prediction made by a scientist based on his observations is known as
MEDIUM
No physicist has ever “seen” an electron. Yet, all physicists believe in the existence of electrons. An intelligent but superstitious man advances this analogy to argue that ‘ghosts’ exist even though no one has ‘seen’ one. How will you refute his argument?
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If two atomic clocks, allowed to run for average life of an Indian (say, 60 years), differ from each other by 0.2s only, calculate the accuracy of the standard atomic clock measuring a time interval of 1s.
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“It is more important to have beauty in the equations of physics than to have them agree with experiments”. The great British physicist P.A.M. Dirac held this view. Criticize this statement. Look out for some which strike you as beautiful.
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“Politics is the art of the possible". Similarly, “Science is the art of the soluble”. Explain this beautiful aphorism on the nature and practice of science.