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(b) 

The difference in the masses of the pieces = 20.17 - 20.15 = 0.02 g (which has only one significant digit !)

Since two is the least number of decimal places, the total mass = 0.02 g.

Given, Length, l = 4.234 m ; Breadth, b = 1.005 m; Height, h = 2.01 cm = 0.0201 m  The length has 4 significant figures The breadth has 4 significant figures The height has 3 significant figures (Since the number is less than 1, hence zeroes after decimal before the first non-zero integer is insignificant) We know, Surface area of a cuboid = 2(l x b + b x h + h x l) = =    =                 ...
(a) The given value is . Since, the number is less than 1, the zeros on the right to the decimal before the first non-zero integer is insignificant. So, the number 7 is the only significant digit.   It has 1 significant digit. (b) The value is For the determination of significant values, we do not consider the power of 10 (Number is not less than 1). The digits 2, 6, and 4 are significant...
Given, Area of the house in the photo = Area of the house on the screen =  Arial magnification,  = Area on the screen / area on photo =  Linear magnification of the projector- screen arrangement  
(a) Take the thread and wrap it around the metre scale. Make sure the coils are packed closely without any space in between. If the diameter of the thread is d and number of turns obtained are n, then (n x d) corresponds to the marking on the metre scale, l. Therefore, the diameter of the thread would be, d = l/n (b) Theoretically, by increasing the number of divisions on the circular...
Given, Magnification of Microscope = 100 The average width of hair under the microscope = 3.5 mm  (20 observations were made to calculate the average i.e. 3.5 mm as an experimental procedure. No need in our calculations.) (Note: When magnified, the width is 3.5 mm. Hence actual width will be less by a factor of magnification value) The average thickness of hair =    
To judge which tool is more precise, we have to find out their least count. Least count defines the margin of error and hence the precision. Hence the instrument with lower least count will be more precise. (a) Least count =    (Taking 1 MSD as 1 mm) (b) Least count = pitch/ number of divisions =  (c) least count = wavelength of light = 400nm to 700nm, that is in the range of  m Therefore, the...
Distance between Sun and Earth = Speed of light x Time taken by light to cover the distance Speed of light = 1 unit Time taken by light to reach earth is 8  minute 20 seconds Time taken =   The distance between Sun and Earth = 1 x 500 = 500 units.
The given statement is true. A dimensional quantity may be small with respect to one reference and maybe large with respect to another reference. Hence, we require a standard reference to judge for comparison. (a) An atom is a very small object with respect to a tennis ball. (but larger than an electron!)  (b) A jet plane moves with great speed with respect to a train.  (c) The mass of Jupiter...
Given, Given new unit of mass =      (In old unit 1kg corresponded to a unit mass, but in new unit  corresponds to a unit mass)  In terms of the new unit,   Similarly in terms of new units,  and    
(a)               (b)    (1 ly = Distance travelled by light in 1 year ) (c)           (d)         
(a) We know,     (Tip: Divide by 100 to convert cm to m)                 The volume of a cube of side a  =                  Volume of cube of side 1 cm (i.e, .01 m ) =  (b) We know,    (Tip: Multiply by 10 to convert cm to mm)                 The surface area of a solid cylinder of radius r and height h =                  Required area =  (c)  (Tip: multiply by 5/18 to convert   )        ...
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