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प्रश्न
Why do we have different units for the same physical quantity?
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उत्तर
The value of any given physical quantity may vary over a wide range, therefore, different uns of the same physical quantity are required. e.g., The length of a pen can be easily measured in cm, the height of a tree can be measured in metres, the distance between two cities can be measured in kilometres and the distance between two heavenly bodies can be measured in light years.
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संबंधित प्रश्न
What do you mean by significant figures?
How many significant figures are present in the 2.0034?
Round up the following upto three significant figures:
34.216
Round up the following upto three significant figures:
10.4107
Round up the following upto three significant figures:
0.04597
Round up the following upto three significant figures:
2808
How many significant figures should be present in the answer of the following calculation?
5 × 5.364
A student measures the thickness of a human hair by looking at it through a microscope of magnification 100. He makes 20 observations and finds that the average width of the hair in the field of view of the microscope is 3.5 mm. What is the estimate on the thickness of hair?
The mean diameter of a thin brass rod is to be measured by vernier callipers. Why is a set of 100 measurements of the diameter expected to yield a more reliable estimate than a set of 5 measurements only?
A LASER is a source of very intense, monochromatic, and unidirectional beam of light. These properties of a laser light can be exploited to measure long distances. The distance of the Moon from the Earth has been already determined very precisely using a laser as a source of light. A laser light beamed at the Moon takes 2.56 s to return after reflection at the Moon’s surface. How much is the radius of the lunar orbit around the Earth?
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):-
the wind speed during a storm
Solve the numerical example.
The diameter of a sphere is 2.14 cm. Calculate the volume of the sphere to the correct number of significant figures.
Which of the following has the highest number of significant figures?
How many significant figures should be present in the answer of the following calculations?
`(2.5 xx 1.25 xx 3.5)/2.01`
Taking into account of the significant figures, what is the value of 9.99 m – 0.0099 m?
The sum of the numbers 436.32, 227.2 and 0.301 in appropriate significant figures is ______.
The mass and volume of a body are 4.237 g and 2.5 cm3, respectively. The density of the material of the body in correct significant figures is ______.
Using the rules for significant figures, the correct answer for the expression `(0.02858 xx 0.112)/(0.5702)` will be ______.
The radius of Earth is expressed as 0.64 × 10⁷ m in scientific notation. What is its order of magnitude and number of significant figures?
