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प्रश्न
Name and define the S.I. unit of time. How is it related to (i) minute (ii) hour, (iii) day, and (iv) year?
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उत्तर
The S.I. unit of time is second. In the short form, we write it as ‘ S ’.
One second is the time interval between the two consecutive ticks that you hear from the pendulum wall clock.
(i) 1 min = 60 s
(ii) 1 h = 60 min. = 3600 s.
(iii) 1 day = 24 h = 86400 s.
(iv) 1 year = 365 days = 3.15 × 107 s.
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संबंधित प्रश्न
Just as precise measurements are necessary in science, it is equally important to be able to make rough estimates of quantities using rudimentary ideas and common observations. Think of ways by which you can estimate the following (where an estimate is difficult to obtain, try to get an upper bound on the quantity):
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| (c) Mass of an apple | (3) Thermometer |
| (d) Period of time for study | (4) Measuring tape |
| (e) Temperature of a body | (5) Graph paper |
| (f) Surface area of a leaf | (6) Metre ruler |
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Find the mass of an object weighing 98 N
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