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Write six common factors that affect accuracy in measurements?

Important Questions on Units and Measurements

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Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

A student measured the diameter of a small steel ball using a screw gauge of least count

0.001 cm .

The main scale reading is

5 mm

and zero division of the circular scale coincides with

25

divisions above the reference level. If the screw gauge has a zero error of

- 0.004 cm .

the correct diameter of the ball is__________

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Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

An accurate measurement implies that

MEDIUM

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

The period of oscillation of a simple pendulum is

T = 2 π \sqrt{\frac{l}{g}} .

Measured value of

l

20.0 cm

, known to

1 mm

accuracy and time for

100

oscillations of the pendulum is found to be

90 s

using a wristwatch of

1 s

resolution. The accuracy in the determination of

g

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Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

The mean length of an object is

5 cm

. Which of the following measurement is most accurate?

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Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

Find the diameter of the Earth (approximately in degrees) as seen from the moon if it is given that the distance between centres of Moon and Earth is about

60

times the radius of Earth.

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Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

Time for

20

oscillations, of a pendulum, is measured as

t_{1} = 39 .6 s

t_{2} = 39 .9 s

and

t_{3} = 39.5 s

. What is the precision in the measurements? What is the accuracy of the measurement?

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Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

The correctness of velocity of an electron moving with velocity

50 m s^{- 1}

0.005 %

. The accuracy with which its position can be measured will be

MEDIUM

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

Time for

20

oscillations of a pendulum is measured as

t_{1} = 39.6 s

;

t_{2} = 39.9 s

;

t_{3} = 39.5 s

; What is the precision in the measurements? What is the accuracy of measurement?

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Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

In our daily life, is it essential to measure everything accurately?

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Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

Which of the following measurements is the most precise?

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Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

The mean length of an object is

5 cm

. Which of the following measurements is the most accurate?

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Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

Just as precise measurements are necessary in science, it is equally important to be able to make rough estimates of quantities using rudimentary ideas and common observations. Think of ways by which you can estimate the following (where an estimate is difficult to obtain, try to get an upper bound on the quantity): "the total mass of rain-bearing clouds over India during the Monsoon".

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Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

In the context of accuracy of measurement and significant figures in expressing results of experiment, which of the following is/are correct?

(a) Out of the two measurements $50.14 cm$ and $0.00025 A$ , the first one has greater accuracy.

(b) If one travels $478 km$ by rail and $397 m$ by road, the total distance travelled is $478 km$ .

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Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

Which of the following measurement is most precise?

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Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

A unit of area, often used in measuring land areas, is the hectare defined as

10^{4}

m^{2}

. An open-pit coal mine consumes 75 hectares of land, down to a depth of 26 m, each year. What volume of earth, in cubic kilometre, is removed in this time?

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Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

The length, breadth and thickness of a block are measured as

125.5 cm, 5.0 cm

and

0.32 cm

, respectively. Which one of the measurement is most accurate?

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Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

The true length of a line is

5.32 m

. The length of the line as measured by two people is

4.23 m

and

4.9 m

, respectively. Then which of the following statements is true?

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Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

In the context of accuracy of measurement and significant figures in expressing results of experiment, which of the following is/are correct?

$(1)$ Out of the two measurements $50.14 cm$ and $0.00025 Ampere$ , the first one has greater accuracy.

$(2)$ If one travels $478 km$ by rail and $397 m$ by road, the total distance travelled is $478 km$ .

MEDIUM

Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

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 microscope is

3.5 mm

. What is the estimate on the thickness of hair in

mm

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Physics>Mechanics>Units and Measurements>Accuracy and Precision of Instruments

To calculate the effective length of pendulum, we measure :-

Write six common factors that affect accuracy in measurements?

Important Questions on Units and Measurements

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