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A student in the laboratory measures thickness of a wire using screw gauge. The readings are 1.22 mm, 1.23 mm, 1.19 mm and 1.20 mm. The percentage error is x/(121)%. The value of x is ______

Asked in JEE Main 28th June 2nd Shift 2022 · Mean and standard deviation of readings

Answer: 150

Step-by-step solution

Readings: 1.22, 1.23, 1.19, 1.20 mm.

Mean: (4.84)/4=1.21 mm.

Deviations: 0.01, 0.02, 0.02, 0.01 mm.

Mean absolute deviation: (0.06)/4=0.015 mm.

Percentage error: (0.015)/(1.21)×100=(1.5)/(1.21)=(150)/(121)%, so x=150.

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