Tamil Nadu
Matriculation Board
Class IX: Physics |
|
Chapter 1: Measurement
|
Very short Answers:
|
Ans.1
The I.S.I stands for Indian Standard Institution. It was set up by Government of India to
certify and test the quality of goods sold or manufactured.
|
Ans.2
The three basic quantities are length, mass and time.
|
|
Ans.3
The screw gauge is based on the principle of a screw, which states that
when a screw is rotated bout its axis it moves through a linear
distance proportional to the amount of rotation given to the screw.
|
Ans.4
The linear distance moved by the screw when one complete rotation is given to it is called
the pitch. It is also the distance between two consecutive threads of the screw.
|
Ans5
The smallest distance that can be measured with a screw gauge is called its least count.
It is the linear distance moved by the screw when it is turned through one division of the
head scale.
|
Ans.6
When the zeroes of the head scale and the pitch scale do not coincide the instrument is
said to have a zero error.
|
Ans.7
The instrument used to measure mass is the physical balance. Length can be measured
accurately using the Vernier Calipers and the screw gauge. Time is measured using the stop
clock.
|
Ans.8
A simple pendulum is formed by tying a string to a metal bob and suspending it from a
support. The time taken to complete one full oscillation is called time period.
|
Ans.9
The basic unit of mass is Kilogram .The basic units for length and time
are meter and second respectively.
|
Ans.10 As civilization developed and life became more complex with man planting crops,
trading goods, purchasing property, manufacturing goods etc it became essential for man to
be assured of the quality of goods traded or manufactured.
|
Ans.11
The Indian Standard Institution provides a certification mark on goods, which show that
the I.S.I approves of the quality of the goods.
|
Ans.12
identical sheets using a scale. We will now divide the thickness obtained by
the number of sheets. This will give us the approximate thickness of one sheet.
|
Ans.13
The choice of instrument used depends on two factors:
a. The degree of accuracy required.
b. The magnitude of the quantity to be measured.
|
Ans.14
The Least count of the meter scale is 1mm while that of the vernier calipers is 0.01 cm.
|
Ans.15
The three instruments which can measure lengths accurately are the Vernier Calipers, Screw
gauge and the Vernier Microscope.
|
Ans.16
The linear scale etched on the sleeve of the screw gauge is called the pitch scale. The
horizontal line drawn on the main scale is called axial line.
|
Ans.17 The
ratchet slips when the end of the screw comes in contact with the object to be measured
and prevents undue pressure on it.
|
Ans.18
The formula for least count of a screw gauge is L.C = (pitch/No. Of divisions on head scale)
|
Ans.19
When the zero of the head scale is above the axial line the error is said to be negative
and the correction is positive.
|
Ans.20
When the zero of the head scale is below the axial line the error is said to be positive
and the correction is negative.
|
Ans.21
The plumb line is used to make the pillar vertical by adjusting the leveling screws.
|
Ans.22
The two scales are the pitch scale and the head scale.
|
Ans.23
The unit of time in the S.I system is the second, which is defined as 1/86400 part of a
mean solar day.
|
Ans.24
The units used to represent the three fundamental quantities namely length, mass and time
are known as fundamental units.
|
| Ans.25
The mass of a body is determined using a physical balance. |
|
Next> |
