In Class 11 Final Exams there will be Case studies and Passage Based Questions will be asked, So practice these types of questions. Study Rate is always there to help you. Free PDF Downloads of CBSE Class 11 Physics Chapter 2 Case Study and Passage-Based Questions with Answers were Prepared Based on the Latest Exam Pattern. Students can solve Class 11 Physics Case Study Questions Units and Measurements to know their preparation level.
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In CBSE Class 11 Physics Paper, There will be a few questions based on case studies and passage-based as well. In that, a paragraph will be given, and then the MCQ questions based on it will be asked.
Units and Measurements Case Study Questions With Answers
Here, we have provided case-based/passage-based questions for Class 11 Physics Chapter 2 Units and Measurements
Case Study/Passage-Based Questions
Case Study 1: The rules for determining the uncertainty or error in the measured quantity in arithmetic operations can be understood from the following examples.
a.) If the length and breadth of a thin rectangular sheet are measured, using a meter scale as 16.2 cm and, 10.1 cm respectively, there are three significant figures in each measurement. It means that the length L may be written as L = 16.2 ± 0.1 cm = 16.2 cm ± 0.6 %.
Similarly, the breadth b may be written as b = 10.1 ± 0.1 cm = 10.1 cm ± 1 %
Then, the error of the product of two (or more) experimental values, using the combination of errors rule, will be L*b = 163.62 cm2 + 1.6% = 163.62 + 2.6 cm2
This leads us to quote the final result as L*b = 164 + 3 cm2. Here 3 cm2 is the uncertainty or error in the estimation of the area of the rectangular sheet.
b.) If a set of experimental data is specified to n significant figures a result obtained by combining the data will also be valid to n significant figures. However, if data are subtracted, the number of significant figures can be reduced. For example, 12.9 g – 7.06 g, both specified to three significant figures, cannot properly be evaluated as 5.84 g but only as 5.8 g, as uncertainties in subtraction or addition combine in a different fashion (smallest number of decimal places rather than the number of significant figures in any of the number added or subtracted).
c.) The relative error of a value of a number specified to significant figures depends not only on n but also on the number itself. For example, the accuracy in the measurement of mass 1.02 g is ± 0.01 g whereas another measurement of 9.89 g is also accurate to ± 0.01 g. The relative error in 1.02 g is
= (± 0.01/1.02) × 100 % = ± 1%
Similarly, the relative error in 9.89 g is = (± 0.01/9.89) × 100 % = ± 0.1 %
Finally, remember that intermediate results in a multi-step computation should be calculated to one more significant figure in every measurement than the number of digits in the least precise measurement.
d.) The nature of a physical quantity is described by its dimensions. All the physical quantities represented by derived units can be expressed in terms of some combination of seven fundamental or base quantities. We shall call these base quantities the seven dimensions of the physical world, which are denoted with square brackets [ ]. Thus, length has the dimension [L], mass [M], time [T], electric current [A], thermodynamic temperature [K], luminous intensity [cd], and amount of substance [mol]. The dimensions of a physical quantity are the powers (or exponents) to which the base quantities are raised to represent that quantity. Note that using the square brackets [ ] around a quantity means that we are dealing with ‘the dimensions of’ the quantity. In mechanics, all the physical quantities can be written in terms of the dimensions [L], [M], and [T]. For example, the volume occupied by an object is expressed as the product of length, breadth, and height, or three lengths. Hence the dimensions of volume are [L] × [L] × [L] = [L3].
When measuring the length and breadth of a rectangular sheet as 16.2 cm and 10.1 cm respectively, what is the uncertainty in the length?
a) 0.6%
b) 0.1%
c) 1%
d) 0.6 cm
Answer: a) 0.6%
In the calculation of the area of a rectangular sheet, the final result is expressed as 164 + 3 cm². What does the 3 cm² represent?
a) The length of the rectangular sheet
b) The breadth of the rectangular sheet
c) The uncertainty or error in the estimation
d) The percentage error in the calculation
Answer: c) The uncertainty or error in the estimation
When dealing with subtraction of numbers like 12.9 g – 7.06 g, how should the result be properly evaluated?
a) 5.84 g
b) 5.8 g
c) 5.9 g
d) 6.0 g
Answer: b) 5.8 g
Which of the following accurately represents the relative error in the measurement of 9.89 g?
a) ± 1%
b) ± 0.1%
c) ± 0.01%
d) ± 0.9%
Answer: b) ± 0.1%
In a multi-step computation, intermediate results should be calculated to how many more significant figures than the least precise measurement?
a) Two more significant figures
b) One more significant figure
c) The same number of significant figures
d) Three more significant figures
Answer: b) One more significant figure
Which of the following represents the dimensions of volume?
a) [L]
b) [L^2]
c) [L3]
d) [L * M * T]
Answer: c) [L3]
How many fundamental or base quantities are used to express all physical quantities in derived units?
a) Five
b) Six
c) Seven
d) Eight
Answer: c) Seven
Case Study 2: Measurement of Physical Quantity: All engineering phenomena deal with definite and measured quantities and so depend on the making of the measurement. We must be clear and precise in making these measurements. To make a measurement, the magnitude of the physical quantity (unknown) is compared.
The record of a measurement consists of three parts, i.e. the dimension of the quantity, the unit which represents a standard quantity, and a number which is the ratio of the measured quantity to the standard quantity.
(i) A device which is used for measurement of length to an accuracy of about 10-5m, is
(a) screw gauge
(b) spherometer
(c) vernier calipers
(d) Either (a) or (b)
Answer: (d) Either (a) or (b)
(ii) Which of the technique is not used for measuring time intervals?
(a) Electrical oscillator
(b) Atomic clock
(c) Spring oscillator
(d) Decay of elementary particles
Answer: (c) Spring oscillator
(iii) The mean length of an object is 5 cm. Which of the following measurements is most accurate?
(a) 4.9 cm
(b) 4.805 cm
(c) 5.25 cm
(d) 5.4 cm
Answer: (a) 4.9 cm
(iv) If the length of rectangle l = 10.5 cm, breadth b = 2.1 cm and minimum possible measurement by scale = 0.1 cm, then the area is
(a) 22.0 cm2
(b) 21.0 cm2
(c) 22.5 cm2
(d) 21.5 cm2
Answer: (a) 22.0 cm2
(v) Age of the universe is about 1010 yr, whereas the mankind has existed for 106 yr. For how many seconds would the man have existed, if age of universe were 1 day?
(a) 9.2 s
(b) 10.2 s
(c) 8.6 s
(d) 10.5 s
Answer: (c) 8.6 s
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