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2 years ago

14

A myopic (nearsighted) lawyer has a far point of 60.0 cm. What is the diopter value of suitable corrective contacts?

1 answer:

Vlada [557]2 years ago

6 0

Answer:

P = -1.67 dP

Explanation:

given,

myopic lawyer has a far point of = 60.0 cm = 0.6 m

If a person is suffering from myopia then he cannot see the farthest object clearly.

Image of far object does not form on the retina so, the image appear to be blur.

using lens formula

$\dfrac{1}{v}-\dfrac{1}{u} = \dfrac{1}{f}$

$-\dfrac{1}{0.6} = \dfrac{1}{f}$

$\dfrac{1}{f} =P$

$P = -\dfrac{1}{0.6}$

P = -1.67 dP

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Oxana [17]

Answer:

20 m/s

Explanation:

Distance covered by man =500m

Time taken by man=25 seconds

Speed of man = distance/time

= 500/25

=20 m/s

4 0

3 years ago

List how many significant figures the numbers contain. A. 205 cm. B. .00004 cm. C. 20 cm. D. 20. Cm.

stiv31 [10]

A. 205 cm
This has 3 significant figures: 2,0 and 5.

B. 0.00004 cm
This has 1 significant figure: 4

C. 20 cm
This has 2 significant figures: 2 and 0.

D. 20. cm
This has 2 significant figures: 2 and 0

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3 years ago

Light of wavelength 650 nm is normally incident on the rear of a grating. The first bright fringe (other than the central one) i

koban [17]

Answer:

A

$N = 1340.86 \ slits / cm$

B

$\theta = 15.7^o$

Explanation:

From the question we are told that

The wavelength is $\lambda = 650 \ nm = 650 *10^{-9} \ m$

The angle of first bright fringe is $\theta = 5^o$

The order of the fringe considered is n =1

Generally the condition for constructive interference is

$dsin (\theta ) = n * \lambda$

=> $d = \frac{1 * 650 *10^{-9 }}{ sin(5)}$

=> $d = 7.458 *10^{-6} \ m$

Converting to cm

$d = 7.458 *10^{-6} \ m = 7.458 *10^{-6} * 100 = 0.0007458 \ cm$

Generally the number of grating pre centimeter is mathematically represented as

$N = \frac{1}{d}$

=> $N = \frac{1}{0.0007458}$

=> $N = 1340.86 \ slits / cm$

Considering question B

From the question we are told that

The first wavelength is $\lambda_1 = 650 \ nm = 650 *10^{-9} \ m$

The second wavelength is $\lambda_2 = 429 \ m = 420 *10^{-9 } \ m$

The order of the fringe is $n = 2$

The grating is $N = 5000 \ slits / cm$

Generally the slit width is mathematically represented as

$d = \frac{1}{N }$

=> $d = \frac{1}{ 5000 }$

=> $d = 0.0002 \ c m = 2.0 *10^{-6} \ m$

Generally the condition for constructive interference for the first ray is mathematically represented as

$d sin(\theta_1) = n * \lambda_1$

=> $\theta_1 = sin^{-1} [\frac{ 2 * \lambda }{d}]$

=> $\theta_1 = sin^{-1} [\frac{ 2 * 650 *10^{-9} }{ 2*10^{-6}}]$

=> $\theta_1 = 40.5 ^o$

Generally the condition for constructive interference for the second ray is mathematically represented as

$d sin(\theta_2) = n * \lambda_2$

=> $\theta_2 = sin^{-1} [\frac{ 2 * \lambda_1 }{d}]$

=> $\theta_2 = sin^{-1} [\frac{ 2 * 420 *10^{-9} }{ 2*10^{-6}}]$

=> $\theta_2 = 24.8 ^o$

Generally the angular separation is mathematically represented as

$\theta = \theta_1 - \theta_1$

=> $\theta = 42.5^o - 24.8^o$

=> $\theta = 15.7^o$

4 0

2 years ago

HELPPP PLEASE !!!!!!!

vlabodo [156]

Explanation:

a) d = ½.a.t²

200 = ½(4)t²

200 = 2t²

t² = 200/2

t² = 100

t =√100 = 10 s

b) Vt = a. t

= 4(10)

= 40 m/s

c) V av. = d/t = 200/10 = 20m/s

6 0

2 years ago

A physical change occurs when a material changes shape or size but the composition of the material does not change. True or Fals

Elden [556K]

It is true that a physical change occurs when a material changes shape or size, but the composition of the material does not change. The correct answer is True.

6 0

2 years ago