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3 years ago

Which structure controls how much light passes through the specimen

Physics

1 answer:

poizon [28]3 years ago

5 0

Answer:

The diaphragm.

Explanation:

A diaphragm is a thin non transparent structure with an aperture at its center. Aperture is the opening in a lens through which light passes to enter the camera. Diaphragm controls the passage of light through specimen. It stops the passage of light except for the light passing through aperture. It also limits the brightness of light reaching the focal plane.

The diaphragm is placed close to the lens, where objects are defocused to the maximum in order to pass every ray from the object through the lens. Diaphragm discards some of those rays but allows multiple rays to move through to produce an image. This means that the size of the aperture controls the amount of light that passes through the lens. The center of the aperture coincides with optical axis of the lens. Iris diaphragm is an example. It is used in modern cameras.

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A 0.439 kg puck, initially at rest on a horizontal, frictionless surface, is struck by a 0.307 kg puck moving initially along th

lesya [120]

Answer:

u2 = 0.266 m/s

Explanation:

Let the left Puck mass at rest = m1 =0.307 Kg

mass of the right puck m2 = 0.439 kg

velocity of m1 before collision v1= 2.19 m/s

velocity of m2 before collision v2 = 0m/s

velocity of m1 after collision u1 =1.19 m/s

velocity of m2 after collision u2 = ? m/s

θ = 37°

<u>Solution:</u>

Before collision:

Momentum (y-axis ) before collision= 0 Kgm/s

Momentum (x-axis ) before collision= m1v1 + m2v2 = 0.307 Kg x 2.19 m/s + 0

= 0.672 Kgm/s

After collision:

Momentum (y-axis ) after collision= m1u1 sinθ + m2u2 sinθ

= 0.307 x 1.19 m/s sin 37 ° + 0.439 x u2 sin 37°

= 0.22 + 0.26 u2

Momentum (x-axis ) after collision= m1u1 cosθ + m2u2 cos θ

= 0.307 x 1.19 m/s cos 37 ° + 0.439 x u2 cos 37°

= 0.29 + 0.35 u2

According to law of conservation momentum

momentum before collision = momentum after collision.

0 + 0.672 Kgm/s = 0.22 Kgm/s + 0.26 kg u2 + 0.29 Kgm/s + 0.35 kg u2

0.672 Kgm/s = 0.51 Kgm/s + 0.61 u2

u2 = 0.266 m/s

6 0

4 years ago

What happens when a candle burns?

slega [8]

Answer:

oxygen is used up is the answer

Explanation:

These vaporized molecules are drawn up into the flame, where they react with oxygen from the air to create heat, light, water vapor (H2O) and carbon dioxide (CO2).

5 0

3 years ago

Can anyone help me in this question?

Anna71 [15]

Answer:

I guess the answer is charging by friction

3 0

3 years ago

if a moving object travels north for a distance of 105 m in 22 sec, what is it’s speed and velocity ?

artcher [175]

Answer:

Speed: 4.8 m/s

Velocity: 4.8 m/s north

Explanation:

Definitions:

- Speed is a scalar quantity, which is equal to the ratio between distance covered (d) and time taken (t):

$s=\frac{d}{t}$

- Velocity is a vector quantity, whose magnitude is equal to the ratio between the displacement of the object and the time taken:

$v=\frac{disp.}{t}$

And it also has a direction (the same as the displacement).

In this problem:

- The object travels a distance of

d = 105 m

In a time interval of

t = 22 s

So its speed is

$s=\frac{105}{22}=4.8 m/s$

- The displacement of the object is the same as the distance in this case, so still 105 m, covered in a time interval of 22 s; this means that the magnitude of the velocity is the same as the speed:

$v=4.8 m/s$

However, velocity is a vector quantity, so it also has a direction: and since the object has moved north, the direction of the velocity is north as well.

3 0

3 years ago

6. Mithra is an unknown planet that has two airless moons. A and B, in circular orbits around it.

Ainat [17]

The acceleration of gravity on Moon B is D) 0.25 m/s2

Explanation:

The data listed in the problem are not clear: find them in the table attached.

The acceleration of gravity on a planet is given by the following equation:

$g=\frac{GM}{R^2}$