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A student performed the experiment of determination of focal l

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A student performed the experiment of determination of focal length of a concave mirror by u-v method using an optical bench of length $1.5 m$ . The focal length of the mirror used is $24 cm$ . The maximum error in the location of the image can be $0.2 cm$ . The 5 sets of $(u, v)$ values recorded by the student (in $cm)$ are $(42, 56), (48, 48), (60, 40), (66, 33), (78, 39)$ . The data set $(s)$ that cannot come from experiment and is (are) incorrectly recorded, is (are)

SELECT MULTIPLE OPTION

(42, 56)

(48, 48)

(66, 33)

(78, 39)

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Mechanics Volume 1 (DC Pandey)

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A student performed the experiment of determination of focal length of a concave mirror by u-v method using an optical bench of length

1.5 m

. The focal length of the mirror used is

24 cm

. The maximum error in the location of the image can be

0.2 cm

. The 5 sets of

(u, v)

values recorded by the student (in

cm)

are

(42, 56), (48, 48), (60, 40), (66, 33), (78, 39)

. The data set

(s)

that cannot come from experiment and is (are) incorrectly recorded, is (are)

8 mins ago

Discuss this question LIVE

8 mins ago

Text solutionVerified

Given

f = - 24 cm

Applying

\frac{1}{v} + \frac{1}{u} = \frac{1}{f}

For

(66, 33) \Rightarrow

\frac{1}{v} = \frac{1}{f} - \frac{1}{u} = \frac{1}{- 24} + \frac{1}{66} = \frac{- 66 + 24}{24 \times 66} = \frac{- 42}{24 \times 66} \Rightarrow v = - \frac{24 \times 66}{42} = - 37.7

But the value of

v = 33

. The absolute error is

37.7 - 33 = 4.7 cm

which is greater than

0.2 cm

. Therefore a wrong reading.

(78, 39)

when

u = 78

then

\frac{1}{v} + \frac{1}{- 78} = \frac{1}{- 24} \Rightarrow v = - 34.67

The absolute error is

39 - 34.67 = 4.33

which is greater than

0.2 cm

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Question Text	A student performed the experiment of determination of focal length of a concave mirror by u-v method using an optical bench of length $1.5 m$ . The focal length of the mirror used is $24 cm$ . The maximum error in the location of the image can be $0.2 cm$ . The 5 sets of $(u, v)$ values recorded by the student (in $cm)$ are $(42, 56), (48, 48), (60, 40), (66, 33), (78, 39)$ . The data set $(s)$ that cannot come from experiment and is (are) incorrectly recorded, is (are)
Topic	Units and Measurements
Subject	Physics
Class	Class 11
Answer Type	Text solution:1
Upvotes	56

Text solutionVerified

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