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A laboratory technician needs to measure the thickness of a very thin metal plate using a screw gauge. The main scale reading is 1.5\ mm, and the circular scale reading is 42. The pitch of the screw gauge is 0.25\ mm, and the least count of the instrument is 0.02\ mm. Due to the delicate nature of the plate, it is important to apply very gentle pressure while measuring its thickness.

Determine the thickness of the metal plate.

Option: 1

1.452\ mm


Option: 2

0.541\ mm


Option: 3

0.585\ mm


Option: 4

0.894\ mm


Answers (1)

best_answer

Given values:
• Main scale reading (M) =1.5\ mm
• Circular scale reading (C) =42
• Pitch of the screw gauge (P) =0.25\ mm
• Least count (LC) =0.02\ mm
The total reading of the screw gauge can be calculated by adding the main scale
reading to the product of the circular scale reading and the least count:

Total reading =M\times(C+LC)
Step 1: Calculate the total reading of the screw gauge:
Total reading =1.5 \mathrm{~mm}+(42 \times 0.02 \mathrm{~mm})=1.5 \mathrm{~mm}+0.84 \mathrm{~mm}=2.34 \mathrm{~mm}

The thickness of the metal plate can be calculated using the formula:

Thickness = Total reading \times P
Step 2: Calculate the thickness of the metal plate:

Thickness =2.34 \mathrm{~mm} \times 0.25 \mathrm{~mm}=0.585 \mathrm{~mm}

The thickness of the metal plate is 0.585\ mm
Therefore, the correct option is (C).

Posted by

rishi.raj

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