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3 years ago

If a lens has a power of -14.50, what is the focal length in mm?

Physics

1 answer:

ra1l [238]3 years ago

5 0

Answer:

Focal length of the lens, f = - 68 mm

Explanation:

Given that,

Power of a lens, P = -14.50 D

We need to find the focal length of the lens. We know that the focal length and the power of lens has inverse relationship. Mathematically, it is given by :

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

f is the focal length of the lens

$f=\dfrac{1}{-14.50}$

f = -0.068 m

f = -68 mm

So, the focal length of the lens is (-68 mm). Hence, this is the required solution.

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1. On one of the shelves in your physics lab is displayed an antique telescope. A sign underneath the instrument says that the t

Ira Lisetskai [31]

Answer:

a) $f_{e}$ = 3,375 cm , b) f₀ = 77.625 cm

Explanation:

The magnification of a telescope is, to see at the far point of vision (infinity image)

m = - f₀ / $f_{e}$

The length of the tube is

L = f₀ + $f_{e}$

a) The focal length of the eyepiece

L = - m $f_{e}$ + $f_{e}$

L = $f_{e}$ (1-m)

$f_{e}$ = L / (1-m)

Let's calculate

$f_{e}$ = 81.0 / (1 - (-23.0)

$f_{e}$ = 3,375 cm

b) the focal length of the target

f₀ = -m $f_{e}$

f₀ = 23 (3.68)

f₀ = 77.625 cm

8 0

3 years ago

An EM wave has a wave length of 956 m, What type of electromagnetic waves is this wave

Assoli18 [71]

The electromagnetic spectrum allows finding the result for the question of type of electromagnetic wave has a wavelength of 956 nm

The wave is in the near infrared range.

The electromagnetic wave is an oscillation of electric fields and magnets field that sustain each other, this wave time has the characteristics that it can travel without a material medium, for which they are of extreme importance.

Consequently the spectrum of electromagnetic waves to each part has been given a different name second to its use, for example

Range Name

Ultraviolet light 200 to 400 nm

Visible light 400 to 700 nm

Infrared light (heat ) 700 nm to 1 mm

The latter is subdivided into:

Near infrared 700 nm to 1000 nm (1 μm)

Medium infrared 1 μm to 30 μm

Far infrared 50 μm to 1000 μm

It indicates that the wavelength of the measured radiation is 956 nm, therefore it is in the near infrared range.

Learn more about the electromagnetism spectrum here: brainly.com/question/23727978

6 0

2 years ago

Is this statement true or false? The next generation of nuclear power plants being built in California and South Africa are even

alexira [117]

Answer:

True

Explanation:

Modern safer and cheaper nuclear reactors can not only meet the range of our long term energy demands, they can also fight global warming.

Modern techniques provide ways to reduce radioactive waste amount. "A closed fuel cycle may be switched on for new kinds of nuclear plants. Alternatively, the waste is chemically dissuaded to transform the reusable element into fuel. This implies that nuclear waste would not be buried.

8 0

3 years ago

Dwayne ‘The Rock’ Johnson needs to escape from the fourth floor of a burning building (in a movie). He ties a rope around his wa

ZanzabumX [31]

Answer:

Final Speed of Dwayne 'The Rock' Johnson = 15.812 m/s

Explanation:

Let's start out with finding the force acting downwards because of the mass of 'The Rock':

Dwayne 'The Rock' Johnson: 118kg x 9.81m/s = 1157.58 N

Now the problem also states that the kinetic friction of the desk in this problem is 370 N

Since the pulley is smooth, the weight of Dwayne Johnson being transferred fully, and pulls the desk with a force of 1157.58 N. The frictional force of the desk is resisting this motion by a force of 370 N. Subtracting both forces we get the resultant force on the desk to be: 1157.58 - 370 = 787.58 N

Now lets use F = ma to calculate for the acceleration of the desk:

787.58 = 63 x acceleration

acceleration = 12.501 m/s

Finally, we can use the motion equation:

$v^2 - u^2 = 2*a*s$

here u = 0 m/s (since initial speed of the desk is 0)

a = 12.501 m/s

and s = 10 m

Solving this we get:

$v^2 - 0 = 2 * 12.501 * 10$

$v = 15.812 m/s$

Since the desk and Mr. Dwayne Johnson are connected by a taught rope, they are travelling at the same speed. Thus, Dwayne also travels at 15.812 m/s when the desk reaches the window.

5 0

3 years ago

A life preserver is thrown from an helicopter straight down to a person in distress. The initial velocity of the life preserver

Leno4ka [110]

Answer:29.627 m

Explanation:

Given

Initial velocity of life preserver(u) is 1.6 m/s

it takes 2.3 s to reach the water

using equation of motion

v=u+at

$v=1.6+9.81\times 2.3$