Units, Dimensions & Errors · JEE Main previous year questions

2018 4 questions

1. Q312018 · 16 Apr 2018 · Shift 1

   The percentage errors in quantities P, Q, R and S are 0.5%, 1%, 3% and 1.5% respectively in the measurement of a physical quantity $\text{A}=\frac{P^3{Q}^2}{\sqrt{R}S}$. The maximum percentage error in the value of A will be :

   1. A.6.0%
   2. B.7.5%
   3. C.8.5%
   4. D.6.5%
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   Answer: D

2. Q312018 · 15 Apr 2018 · Shift 1

   The relative error in the determination of the surface area of sphere is $\alpha$. Then the relative error in the determination of its volume is :

   1. A.$\frac{3}{2}\alpha$
   2. B.$\frac{2}{3}\alpha$
   3. C.$\frac{5}{2}\alpha$
   4. D.$\alpha$
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   Answer: A

3. Q452018 · 15 Apr 2018 · Shift 1

   In a screw gauge, 5 complete rotations of the screw cause it to move a linear distance of $0.25cm$. There are 100 circular scale divisions. The thickness of a wire measured by this screw gauge gives a reading of 4 main scale divisions and 30 circular scale divisions. Assuming negligible zero error, the thickness of the wire is :

   1. A.$0.4300cm$
   2. B.$0.2150cm$
   3. C.$0.3150cm$
   4. D.$0.0430cm$
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   Answer: B

4. Q312018 · 8 Apr 2018 · Shift 1

   The density of a material in the shape of a cube is determined by measuring three sides of the cube and its mass. If the relative errors in measuring the mass and length are respectively 1.5% and 1%, the maximum error in determining the density is:

   1. A.6%
   2. B.2.5%
   3. C.3.5%
   4. D.4.5%
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   Answer: D