Units and Measurement
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A screw gauge has 50 divisions on its circular scale. The circular scale is 4 units ahead of the pitch scale marking, prior to use. Upon one complete rotation of the circular scale, a displacement of 0.5 mm is noticed on the pitch scale. The nature of zero error involved, and the least count of the screw gauge, are respectively:
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A screw gauge has 50 divisions on its circular scale. The circular scale is 4 units ahead of the pitch scale marking, prior to use. Upon one complete rotation of the circular scale, a displacement of 0.5 mm is noticed on the pitch scale. The nature of zero error involved, and the least count of the screw gauge, are respectively:
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L.C. = 0.5 mm / 50 = 10? ² mm = 10? m = 10µm
The dimension of , where is magnetic field and is the magnetic permeability of vacuum, is
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The dimension of , where is magnetic field and is the magnetic permeability of vacuum, is
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Magnetic energy per unit volume
In order to determine the young's modulus of a wire of radius 0.2 cm (measured using a scale of least count = 0.001 cm) and length 1m (measured using a scale of least count = 1 mm), a weight of mass 1 kg (measured using a scale of least count = 1g) was hanged to get the elongation of 0.5 cm (measured using a scale of least count 0.001 cm.) What will be the fractional error in the value of young's modulus determined by this experiment?
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In order to determine the young's modulus of a wire of radius 0.2 cm (measured using a scale of least count = 0.001 cm) and length 1m (measured using a scale of least count = 1 mm), a weight of mass 1 kg (measured using a scale of least count = 1g) was hanged to get the elongation of 0.5 cm (measured using a scale of least count 0.001 cm.) What will be the fractional error in the value of young's modulus determined by this experiment?
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using hook's law:
σ = Yε ⇒ f/A = Y (x/l) ⇒ Y = fl/ (xA) = fl/ (xπr²)
Using error analysis formula:
ΔY/Y = Δf/f + Δl/l + Δx/x + 2Δr/r
%error in Y = [ (Δm/m) + (Δl/l) + (Δx/x) + 2 (Δr/r) ] × 100
= [ (1/1000) + (1/1000) + (0.001/0.5) + 2 (0.001/0.2) ] × 100
= [ 0.001 + 0.001 + 0.002 + 0.01 ] × 100 = 1.4%
A physical 'y' is represented by the formula y = m²r⁻⁴gˣl⁻³/² if the percentage errors found in y, m, r, l and g are 18, 1, 0.5, 4 and p respectively, then find the value of x and p.
A physical 'y' is represented by the formula y = m²r⁻⁴gˣl⁻³/² if the percentage errors found in y, m, r, l and g are 18, 1, 0.5, 4 and p respectively, then find the value of x and p.
Δy/y = 2Δm/m + 4Δr/r + |x|Δg/g + (3/2)Δl/l
18 = 2 (1) + 4 (0.5) + |x|p + (3/2)4
18 = 2 + 2 + |x|p + 6 = 10 + |x|p
8 = |x|p
From the options, if x=8, p=±1. If x=16/3, p=±3/2. If x=5, p=±8/5. If x=4, p=±2.
Option B gives x=16/3, and p is not among the options.
Option A gives x=5, p not among options.
Option
Match List I with List II.
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Match List I with List II.
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[C] = Q/V = Q/ (W/Q) = Q²/W = (A²T²)/ (M¹L²T? ²) = M? ¹L? ²T? A²
[ε? ] = C/ (4πr²) * (Fr²/q²) = M? ¹L? ³T? A²
[µ? ] = 4πrF/I²l = M¹L¹T? ²A? ²
[E] = F/q = (MLT? ²)/ (AT) = MLT? ³A? ¹
Student A and Student B used two screw gauges of equal pitch and 100 equal circular divisions to measure the radius of a given wire. The actual value of the radius of the wire is 0.322 cm. The absolute value of the difference between the final circular scale readings observed by the students A and B is _______. [Figure shows position of reference 'O' when jaws of screw gauge are closed]. Given pitch = 0.1 cm.
(Figure A shows a positive zero error with the 5th division of the circular scale coinciding with the reference line. Figure B shows a negative zero error with the 92nd division of the circular scale coinciding with the reference line.)
Student A and Student B used two screw gauges of equal pitch and 100 equal circular divisions to measure the radius of a given wire. The actual value of the radius of the wire is 0.322 cm. The absolute value of the difference between the final circular scale readings observed by the students A and B is _______. [Figure shows position of reference 'O' when jaws of screw gauge are closed]. Given pitch = 0.1 cm.
(Figure A shows a positive zero error with the 5th division of the circular scale coinciding with the reference line. Figure B shows a negative zero error with the 92nd division of the circular scale coinciding with the reference line.)
Difference in Reading = Positive Zero Error - Negative Zero Error
= (+5) - [- (100-92)]
= 5 - [-8]
= 13
Assertion A: If in five complete rotations of the circular scale, the distance travelled on main scale of the screw gauge is 5 mm and there are 50 total divisions on circular scale, then least count is 0.001 cm.
Reason R: Least Count = Pitch / (Total divisions on circular scale)
In the light of the above statement, choose the most appropriate answer from the options given below:
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Assertion A: If in five complete rotations of the circular scale, the distance travelled on main scale of the screw gauge is 5 mm and there are 50 total divisions on circular scale, then least count is 0.001 cm.
Reason R: Least Count = Pitch / (Total divisions on circular scale)
In the light of the above statement, choose the most appropriate answer from the options given below:
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Least count = Pitch / (Total divisions on circular scale)
In 5 revolution, distance travelled = 5mm
? In 1 revolution, distance travelled = 1mm
So least count = 1/50 = 0.02mm = 0.002 cm
So, Assertion is not correct but reason is correct



