Advertisements
Advertisements
Question
The relative density of lead is 11.3. Its density is ______ g cm–3or ______ kg m–3.
Advertisements
Solution 1
The relative density of lead is 11.3. Its density is 11.3 g cm–3or 11.3 × 10-3 kg m–3.
Explanation:
Relative density of a lead is given by the relation,
`"Relative density" = "Density of lead"/"Density of water"`
Density of water = 1 g/cm3
Density of lead = Relative density of lead x Density of water
= 11.3 × 1
= 11.3 g/`"cm"^-3`
Again 1g = `1/1000` kg
`1 cm^3 = 10^(-6)"m"^3`
`1 "g/cm"^3 = 10^(-3)/10^(-6) "kg"/"m"^3 = 10^-3 "kg/m"^-3`
`:. 11.3 "g/cm"^-3 = 11.3 xx 10^-3 "kg/m"^-3`
Solution 2
Density = 11.3 g/cm3
=11.3 × 103 kg m-3 [1 kg =103 g, 1 m = 102 cm]
=11.3 × 103 kg m-3
APPEARS IN
RELATED QUESTIONS
How many significant figures are present in the 5005?
How many significant figures should be present in the answer of the following calculation:-
`(0.02856 xx 298.15 xx 0.112)/0.5785`
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?
Precise measurements of physical quantities are a need of science. For example, to ascertain the speed of an aircraft, one must have an accurate method to find its positions at closely separated instants of time. This was the actual motivation behind the discovery of radar in World War II. Think of different examples in modern science where precise measurements of length, time, mass etc. are needed. Also, wherever you can, give a quantitative idea of the precision needed.
It is a well known fact that during a total solar eclipse the disk of the moon almost completely covers the disk of the Sun. From this fact and from the information you can gather from examples 2.3 and 2.4, determine the approximate diameter of the moon.
State the number of significant figures in the following:
0.007 m2
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
Answer the following question.
Describe what is meant by order of magnitude.
Write the rules for determining significant figures.
If the density of a solution is 3.12 g mL–1, the mass of 1.5 mL solution in significant figures is ______.
The sum of the numbers 436.32, 227.2 and 0.301 in appropriate significant figures is ______.
The numbers 2.745 and 2.735 on rounding off to 3 significant figures will give ______.
Why do we have different units for the same physical quantity?
How many significant figures are present in the measurement 2007 grams?
The radius of Earth is written as 0.64 × 10⁷ m in scientific notation. What is its order of magnitude?
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?
A length L is measured as 125 m, which is also written as 12500 cm and 125000 mm. How many significant figures does this measurement have?
