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- Question
Which one of the following elements is used as a timekeeper in atomic clocks?
Options- A. Potassium
- B. Caesium
- C. Calcium
- D. Magnesium
- Correct Answer
- Caesium
ExplanationWhen exposed to certain frequencies of radiation, such as radio waves, the subatomic particles called electrons that orbit an atom's nucleus will "jump" back and forth between energy states. Clocks based on this jumping within atoms can therefore provide an extremely precise way to count seconds.It is no surprise then that the international standard for the length of one second is based on atoms. Since 1967, the official definition of a second is 9,192,631,770 cycles of the radiation that gets an atom of the element called caesium to vibrate between two energy states.
- 1. United Nations adapted a Charter of Economic Rights in the year
Options- A. 1969
- B. 1974
- C. 1956
- D. 1964 Discuss
- 2. The intersecting lines drawn on maps and globes are
Options- A. latitudes
- B. longitudes
- C. geographic grids
- D. None of the above Discuss
- 3. The budget deficit means
Options- A. the excess of total expenditure, including loans, net of lending over revenue receipts
- B. difference between revenue receipts and revenue expenditure
- C. difference between all receipts and all the expenditure
- D. fiscal deficit less interest payments Discuss
- 4. The infrared radiation by sun are strongly absorbed by
Options- A. carbon dioxide
- B. water vapours
- C. carbon dioxide and water vapours
- D. ozone Discuss
- 5. The Board of Industrial and Financial Reconstruction (BIFR) came into existence in
Options- A. 1984
- B. 1986
- C. 1987
- D. 1989 Discuss
- 6. Eugenics is the study of
Options- A. altering human beings by changing their genetic components
- B. people of European origin
- C. different races of mankind
- D. genetic of plants Discuss
- 7. The highest mountains in Africa, which is not part of any mountains chain, is
Options- A. Mt. Aconcagua
- B. Mt. Kilimanjaro
- C. Mt. Kosciuszko
- D. Mont Blanc Discuss
- 8. How many former republics of USSR have become members of the Commonwealth of Independent States?
Options- A. 11
- B. 10
- C. 12
- D. 9 Discuss
- 9. The length of the tropical years (the time interval between successive occurrences of the spring equinox) is decreasing very slowly as a result of
Options- A. small, progressive changes in the earth's rotational speed
- B. small, progressive change in earth's orbit around the sun
- C. both (a) and (b)
- D. None of the above Discuss
- 10. The term Khalisa in Mughal administration signified the
Options- A. entire Imperial establishment
- B. land owned b the emperor himself
- C. religious land grants
- D. land from where revenue was collected for the Imperial Treasury Discuss
More questions
Correct Answer: 1974
Correct Answer: geographic grids
Correct Answer: difference between all receipts and all the expenditure
Correct Answer: carbon dioxide
Correct Answer: 1987
Correct Answer: altering human beings by changing their genetic components
Correct Answer: Mt. Kilimanjaro
Correct Answer: 11
Correct Answer: both (a) and (b)
Correct Answer: land owned b the emperor himself
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