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Topic Question Set

Q 1 :    

The area of a square is 5.29 cm2. The area of 7 such squares taking into account the significant figures is                      [2019]

  • 37cm2

     

  • 37.0cm2

     

  • 37.03cm2

     

  • 37.030cm2

     

(C) Total Area = A1+A2+...A7=A+A+...7 times = 37.03 cm2. Addition of 7 terms all having 2 terms beyond decimal, so final answer must have 2 terms beyond decimal (as per rules of significant digits.)

Q 2 :    

A student determined Young's modulus of elasticity using the formula Y=MgL34bd3δ. The value of g is taken to be 9.8m/s2, without any significant error, his observation is as following.                                            [2021]

Physical quantity Least count of the equipment used for measurement Observed value
Mass (M)                                         1 g            2 kg
Length of bar (L)                                         1 mm            1 m
Breadth of bar (b)                                         0.1 mm            4 cm
Thickness of bar (d)                                         0.01 mm            0.4 cm
Depression (δ)                                         0.01 mm            5 mm

 

Then the fractional error in the measurement of Y is

  • 0.155

     

  • 0.0083

     

  • 0.083

     

  • 0.0155

     

(D) Young's modulus of elasticity,

      Y=MgL34bd3δ

       ∆YY=∆MM+3∆LL+∆bb+3∆dd+∆δδ

        ∆YY=10-32+3×10-31+10-24+3×10-24+10-25=0.0155

Q 3 :    

Time periods of oscillation of the same simple pendulum measured using four different measuring clocks were recorded as 4.62 s, 4.632 s, 4.6 s and 4.64 s. The arithmetic mean of these reading in correct significant figure is                                                   [2024]

  • 4.6 s

     

  • 5 s

     

  • 4.623 s

     

  • 4.62 s

     

(A)  In four values least significant digit value is 4.6 so first round off every value according to this

      4.62→4.6, 4.632→4.6, 4.6→4.6, 4.64→4.6

       avg=4.6+4.6+4.6+4.64=4.6

 

Q 4 :    

In an expression a×10b                                                           [2024]

 

  • a is order of magnitude for b≤5

     

  • b is order of magnitude for 5<a≤10

     

  • b is order of magnitude for a≥5

     

  • b is order of magnitude for a≤5

     

(D)  a×10b

       if a≤5 order is b

       a>5 order is b+1

 

Q 5 :    

Match List - I with List - II.                                            [2024]

  List - I (Numbers)   List - 2 (Significant figures)
A 1001 (I)                      3
B 010.1 (II)                      4
C 100.100 (III)                      5
D 0.0010010 (IV)                      6

 

Choose the correct answer from the given below:

  • (A)-(II), (B)-(I), (C)-(IV), (D)-(III)

     

  • (A)-(IV), (B)-(III), (C)-(I), (D)-(II)

     

  • (A)-(I), (B)-(II), (C)-(III), (D)-(IV)

     

  • (A)-(III), (B)-(IV), (C)-(II), (D)-(I)

     

(A)      (A) 1001→4

           (B)  010.1→3

           (C) 100.100→6

           (D)  0.0010010→5