# L9 – Example 2.9 to 2.12 Units and Measurements

## Topics/Questions discussed in this video:

Example 2.9 The resistance R = V/I where V = (100 ± 5)V and I = (10 ± 0.2)A. Find the percentage error in R.

Example 2.10 Two resistors of resistances R1 = 100±3 ohm and R2 = 200 ± 4 ohm are connected
(a) in series,
(b) in parallel.
Find the equivalent resistance of the
(a) series combination,
(b) parallel combination.
Use for (a) the relation R = R1 + R2 and for (b) \frac{1}{R} = \frac{1}{R_1} + \frac{1}{R_2} and \frac{\Delta R}{R`^{2}} = \frac{\Delta R_1}{{R_1}^2} + \frac{\Delta R_2}{{R_2}^2}

Example 2.11 Find the relative error in Z, if Z = \frac{A^4 B^{\frac{1}{3}}}{C D^{\frac{3}{2}}}.

Example 2.12 The period of oscillation of a simple pendulum is T = 2 \pi \sqrt{\frac{L}{g}}
Measured value of L is 20.0 cm known to 1 mm accuracy and time for 100 oscillations of the pendulum is found to be 90 s using a wrist watch of 1 s resolution. What is the accuracy in the determination of g ?

## L11 – Exercise 2.7 to 2.15 Units and Measurements

Topics/Questions discussed in this video: Exercise 2.7 A student measures the thickness of a human hair by looking at it through a microscope of  magnification 100. He makes 20 observations and finds that the average width of the hair in the field of view of the...

## L3 – Parallax Method Units and Measurements

Topics/Questions discussed in this video:   Example 2.2 A man wishes to estimate the distance of a nearby tower from him. He stands at a point A in front of the tower C and spots a very distant object O in line with AC. He then walks perpendicular to AC up to B,...

## L6 – Significant Figures Units and Measurements

Topics/Questions discussed in this video: Significant Figures Units and Measurements Download PDF of Notes

## L8 – Example 2.6 – Units and Measurements

Topics/Questions discussed in this video: Example 2.6 Two clocks are being tested against a standard clock located in a national laboratory. At 12:00:00 noon by the standard clock, the readings of the two clocks are : MondayTuesdayWednesday Thursday FridaySaturday...

## L5 – Example 2.8 – Errors in sum, difference, product, divide and power

Topics/Questions discussed in this video: In this lecture I am discussing Example 2.8 Errors in sum, difference, product, divide and power for Chapter 2 Units and Measurements Class 11 Physics IIT Jee Mains/Neet. Example 2.8 The temperatures of two bodies measured by...

## L2 – Basics of Angles Units and Measurements

Topics/Questions discussed in this video:   In this lecture I am discussing the Basics of Angles, Basics of Radian, Conversation Between Degree and Radian of Chapter 2 Units and Measurements Class 11 Physics For IIT Jee Mains/Neet having explanations from basic...