Tag: fundamental and derived units

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Multiple choice physics measurements and units some examples of derived units fundamental and derived quantities fundamental and derived units

Among the following identify derived quantities?

  1. Speed

  2. Temperature

  3. Volume

  4. Mass
Reveal answer Fill a bubble to check yourself
A,C Correct answer
Explanation

(A) Speed $\displaystyle = \frac{distance}{time}$ - a derived quantity of length and time.
(B) Temperature - fundamental quantity.
(C) Volume (cube of length) - a derived quantity of length.
(D) Mass - fundamental quantity.

Multiple choice physics measurements and units some examples of derived units fundamental and derived quantities fundamental and derived units

Which of the following is larger unit of density ?

  1. $gm^{-3}$
  2. $gkm^{-3}$
  3. $kgm^{-3}$
  4. $gcm^{3}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
m is the mass of an object divided by its volume. Density often has units of grams per cubic centimeter (g/cm3). Remember, grams is a mass and cubic centimeters is a volume (the same volume as 1 milliliter).
Multiple choice chemistry substances in the surroundings - their states and properties measurement of density properties of substances fundamental and derived units

The density of a cuboid of mass 200 g with dimensions 2 cm $\times$ 4 cm $\times$ 5 cm is

  1. 1000 kg m$^{-3}$
  2. 3000 kg m$^{-3}$
  3. 5000 kg m$^{-3}$
  4. 2000 kg m$^{-3}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The density of a body is defined as the amount of substance contained per unit volume.
Density $=\dfrac{mass}{volume}$

$\displaystyle d = \frac{0.2 kg}{40  cm^3} = \frac{0.2 \times 10^6}{40} kg  m^{-3}$

$=5000  kg  m^{-3}$
Multiple choice chemistry substances in the surroundings - their states and properties measurement of density properties of substances fundamental and derived units

A wire of length 50 cm has a mass of 20 gm. It its radius is halved by stretching, its new mass per unit length will be

  1. 0.4 g cm$^{-1}$
  2. 0.2 kg m$^{-1}$
  3. 0.1 g cm$^{-1}$
  4. 0.2 g cm$^{-1}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

On stretching, volume remains constant. Hence on decreasing the radius by half, the length of the wire becomes quadrupled. 
Mass per unit length $\displaystyle = \frac{20}{4 \times 50 cm}$
$=0.1  g  cm^{-1}$

Multiple choice chemistry substances in the surroundings - their states and properties measurement of density properties of substances fundamental and derived units

If 5 litres of kerosene has a mass of 5 kg, then what is the density of kerosene?

  1. 500 kg/$m^3$
  2. 1000 kg/$m^3$
  3. 100 kg/$m^3$
  4. 50 kg/$m^3$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Density of kerosene $= \displaystyle \frac{mass}{volume}$
$\displaystyle = \frac{5  kg}{5  litres}= \frac{5kg}{5 \times 10^{-3}m^3} = 1000 kg  m^{-3}$

Multiple choice chemistry substances in the surroundings - their states and properties measurement of density properties of substances fundamental and derived units

Two spheres are having the ratio of their densities 1:3 and masses in 3:4 respectively. Find the ratio of their volumes. i.e $\dfrac{V _1}{V _2}$

  1. 1:3

  2. 3:1

  3. 4:9

  4. 9:4
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$\displaystyle \frac{d _1}{d _2} = \frac{1}{3} ; \frac{m _1}{m _2} = \frac{3}{4}$
$d = m/v$
$\therefore \displaystyle \frac{V _1}{V _2}  = \frac{m _1}{m _2} \times \frac{d _2}{d _1} = \frac{3}{4} \times \frac{3}{1} = 9:4$

Multiple choice chemistry substances in the surroundings - their states and properties measurement of density properties of substances fundamental and derived units

If the mass of a body is 12.1 g and its density is 2.2 g/cc, its volume is.

  1. $5.5 cm^3$
  2. $8$ cc
  3. $11$ cc
  4. $55$ cc
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Given:

mass $(m)=12.1g$
density $(d)=2.2g/cc$
Let the volume be $v$
As $density=\dfrac{mass}{volume}$
$d=\dfrac{m}{v}$
$v=\dfrac{m}{d}$
$v=\dfrac{12.1}{2.2}=5.5cc$