This table is explain about common misconception of measurements verses fact of the measurements
Common Misconception |
Fact |
Light year is
commonly understood as a unit of time |
Light year is a
unit of distance. One light year is the distance travelled by light through
space in one year. 1 light year =
9.46x1015m |
In measurement of
all liquids 1kg=1 liter |
Mass of liquid can
be measure in kg while the volume of liquid can be measured in liter. |
System of units
The fundamental units of length, mass and time taken are to
form a system of units. For measuring various physical quantities following
systems are commonly adopted.
Name of the system |
Unit |
||
Length |
Mass |
Time |
|
.
FPS |
foot |
pound |
Second |
.
CGS |
centimeter |
Gram |
second |
.
MKS |
meter |
kilogram |
second |
Measurement of volume
of irregular solids can be made as follows.
S.No |
To find the volume of |
Description |
1. |
Solids insoluble
in water, (a) But heavier than water |
Take some water in
a measuring jar and let its volume be v1 cm3. Immerse
the solid completely in water using a string. The water level raises and let
the final level be v2 cm3. So, volume of solid = (V2-V1)
cm3 |
|
(b)Lighter than
water |
Let the volume of
water be v1 cm3 when a sinker is immersed in it. Tie
the solid to the sinker and immerse it into the water, now note the final
level of water and let it be v2 cm3. Then volume of
solid = (v2-v1) cm3 |
2. |
A single drop of
water |
1. Take a clean
burette with water. Clamp it upright. 2. Remove any air
bubbles formed. 3. Now allow water
to trickle slowly drop by drop, count number of drops when known volume of
water has been drained out. 4. Average volume
of a single drop = Volume of water drained out/number of drops |
3. |
Average volume of
lead shots |
1.Take a measuring
jar with water of volume v1 cm3 2.Drop n number of
lead shots into the water and note the final level of water as v2
cm3 3.Average volume
of lead shot = (v2 –
v1 /n) cm3 |