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3 years ago

1. The nearest distance of distinct vision of

Physics

1 answer:

Vedmedyk [2.9K]3 years ago

3 0

Answer:

The focal length of the lens is +30 and it is a convex lens.

Explanation:

Given that,

The nearest distance of distinct vision of a hypermetropial person is 60 cm, v = -60 cm

The distance is reduced by 20 cm, u = -20 cm

We need to find the nature and focal length of the lens.

Let f be the focal length of the lens. Using lens formula,

$\dfrac{1}{v}-\dfrac{1}{u}=\dfrac{1}{f}\\\\\dfrac{1}{f}=\dfrac{1}{(-60)}-\dfrac{1}{(-20)}\\\\f=+30\ cm$

So, the focal length of the lens is +30 and it is a convex lens.

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According to the Newton’s first law of motion , which of the following objects will change in motion

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The correct answer is C

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3 years ago

A solenoidal coil with 22 turns of wire is wound tightly around another coil with 330 turns. The inner solenoid is 21.0 cm long

Airida [17]

Answer:

$0.00027646\ T$

$2.33\times 10^{-5}\ H$

-0.04194 V

Explanation:

$N_2$ = Number of turns in outer solenoid = 330

$N_1$ = Number of turns in inner solenoid = 22

$I_1$ = Current in inner solenoid = 0.14 A

$\dfrac{dI_2}{dt}$ = Rate of change of current = 1800 A/s

$\mu_0$ = Vacuum permeability = $4\pi \times 10^{-7}\ H/m$

r = Radius = 0.0115 m

Magnetic field is given by

$B=\mu_0\dfrac{N_2}{l}I\\\Rightarrow B=4\pi \times 10^{-7}\times \dfrac{330}{0.21}\times 0.14\\\Rightarrow B=0.00027646\ T$

The average magnetic flux through each turn of the inner solenoid is $0.00027646\ T$

Magnetic flux is given by

$\phi=BA\\\Rightarrow \phi=0.00027646\times \pi 0.0115^2\\\Rightarrow \phi=1.14862\times 10^{-7}\ wb$

Mutual inductance is given by

$M=\dfrac{N_1\phi}{I}\\\Rightarrow M=\dfrac{22\times 1.14862\times 10^{-7}}{0.14}\\\Rightarrow M=2.33\times 10^{-5}\ H$

The mutual inductance of the two solenoids is $2.33\times 10^{-5}\ H$

Induced emf is given by

$\epsilon=-M\dfrac{dI_2}{dt}\\\Rightarrow \epsilon=-2.33\times 10^{-5}\times 1800\\\Rightarrow \epsilon=-0.04194\ V$

The emf induced in the outer solenoid by the changing current inthe inner solenoid is -0.04194 V

3 0

3 years ago

1. A body moving with uniform acceleration of 10 m/s2 covers a distance of 320 m. if its initial velocity was 60 m/s. Calculate

gladu [14]

Answer:

v² = u² + 2as

v² = 3600 + 6400

v² = 10000

v = 100

Explanation:

final velocity is 100 m/s

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Explanation:

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3 years ago

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A single-slit diffraction pattern is formed on a distant screen. If the width of the single slit through which light passes is r

jarptica [38.1K]

Answer:

The width of the central bright fringe will increase

Explanation:

In a single-slit diffraction pattern, the distance of the nth-minimum from the central maximum on the screen is given by

$y=\frac{n \lambda D}{d}$

where

$\lambda$ is the wavelength of the wave

D is the distance of the screen from the slit

d is the width of the slit

The width of the central bright fringe is equal to twice the value of y=1 (first minimum), so:

$w=2 y(n=1) = \frac{2\lambda D}{d}$

And we see that it is inversely proportional to the width of the slit: therefore, if the width of the slit is reduced, the width of the central brigh fringe will increase.

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3 years ago