Question Details

A screw gauge gives the following readings when used to measure the diameter of a wire

Main scale reading : 0 mm

Circular scale reading : 52 divisions

Given that 1 mm on main scale corresponds to 100 divisions on the circular scale.

The diameter of the wire from the above data is :

Options

A

0.52 cm

B

0.026 cm

C

0.26 cm

D

0.052 cm

Correct Answer :

0.052 cm

Solution :

To find the diameter of the wire, we need to calculate the least count of the screw gauge and then use the readings to determine the total measurement.

Step 1: Understand the given parameters
Main scale reading (MSR) = 0 mm
Circular scale reading (CSR) = 52 divisions
Pitch of the screw gauge (the distance corresponding to one full rotation or the smallest division on the main scale) = 1 mm
Total number of circular scale divisions = 100

Step 2: Calculate the Least Count (LC) of the screw gauge
The least count is the smallest value that can be measured accurately by the instrument, calculated as:
Least Count (LC)=PitchTotal circular scale divisions
Substituting the given values:
LC=1 mm100=0.01 mm

Step 3: Calculate the measured diameter
The formula for the total reading (diameter) is:
Total Reading=Main Scale Reading (MSR)+(Circular Scale Reading (CSR)×Least Count (LC))
Substituting the values we have:
Diameter=0 mm+(52×0.01 mm)
Diameter=0.52 mm

Step 4: Convert the diameter to centimeters (cm)
Since the options are given in centimeters, we convert millimeters to centimeters by dividing by 10 (since 1 cm=10 mm):
Diameter=0.5210 cm=0.052 cm

Therefore, the correct diameter of the wire is 0.052 cm.

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