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Units and Measurements · Question 38

JEE Main 2025 (Online) 3rd April Evening ShiftNumericalEasy📈 Topic in 29% papers+4
1

A physical quantity C is related to four other quantities p, q, r and s as follows C = pq2r3 s The percentage errors in the measurement of p, q, r and s are 1\%, 2\%, 3\% and 2\%, respectively. The percentage error in the measurement of C will be %

Answer

15

Solution

For C = pq2r3 s1/2, the maximum relative errors add, each multiplied by its power:

CC 100 = pp 100 + 2 qq 100 + 3 rr 100 + 12 ss 100

= 1 + 2(2) + 3(3) + 12(2)

= 1 + 4 + 9 + 1

= 15\%

Answer: 15

JEE Main 2025 (Online) 3rd April Evening Shift

Keep practising — Units and Measurements

2

Match List I with List II. Choose the correct answer from the options given below:

  1. (A)-(II), (B)-(III), (C)-(IV), (D)-(I)
  2. (A)-(IV), (B)-(II), (C)-(I), (D)-(III)
  3. (A)-(IV), (B)-(I), (C)-(II), (D)-(III)
  4. (A)-(I), (B)-(IV), (C)-(III), (D)-(II)
JEE Main 2025 (Online) 2nd April Morning Shift
3

The equation for real gas is given by (P + aV2 )(V - b) = RT, where P, V, T and R are the pressure, volume, temperature and gas constant, respectively. The dimension of ab-2 is equivalent to that of :

  1. Compressibility
  2. Planck's constant
  3. Energy density
  4. Strain
JEE Main 2025 (Online) 2nd April Morning Shift
4

If 0 and 0 are the permeability and permittivity of free space, respectively, then the dimension of ( 1 0 0 ) is :

  1. T2/L
  2. L2/T2
  3. T2/L2
  4. L/T2
JEE Main 2025 (Online) 2nd April Evening Shift
5

Given a charge q, current I and permeability of vacuum 0. Which of the following quantity has the dimension of momentum ?

  1. qI/ 0
  2. q2 0 I
  3. q 0/I
  4. q 0 I
JEE Main 2025 (Online) 2nd April Evening Shift
6

The pair of physical quantities not having the same dimensions is :

  1. Angular momentum and Planck's constant
  2. Torque and energy
  3. Surface tension and impulse
  4. Pressure and Young's modulus
JEE Main 2025 (Online) 29th January Morning Shift
7

The expression given below shows the variation of velocity (v) with time (t), v = At2 + BtC + t. The dimension of ABC is :

  1. [ M0L1T-2]
  2. [ M0L2T-3]
  3. [ M0L2T-2]
  4. [ M0L1T-3]
JEE Main 2025 (Online) 29th January Morning Shift
8

In a measurement, it is asked to find modulus of elasticity per unit torque applied on the system. The measured quantity has dimension of [MaLbTc]. If b = -3, the value of c is .

JEE Main 2025 (Online) 28th January Morning Shift
9

A tiny metallic rectangular sheet has length and breadth of 5 mm and 2.5 mm, respectively. Using a specially designed screw gauge which has pitch of 0.75 mm and 15 divisions in the circular scale, you are asked to find the area of the sheet. In this measurement, the maximum fractional error will be x100 where x is .

JEE Main 2025 (Online) 28th January Morning Shift
10

Match List - I with List - II. Choose the correct answer from the options given below:

  1. (A)-(II), (B)-(I), (C)-(IV), (D)-(III)
  2. (A)-(I), (B)-(III), (C)-(IV), (D)-(II)
  3. (A)-(III), (B)-(I), (C)-(IV), (D)-(II)
  4. (A)-(III), (B)-(I), (C)-(II), (D)-(IV)
JEE Main 2025 (Online) 28th January Evening Shift

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