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3 years ago

100 POINTS AND BRAINLIEST! What were the Magdeburg Hemispheres?

2 answers:

amm18123 years ago

8 0

The Magdeburg hemispheres are a pair of large copper hemispheres, with mating rims. They were used to demonstrate the power of atmospheric pressure. When the rims were sealed with grease and the air was pumped out, the sphere contained a vacuum and could not be pulled apart by teams of horses.

pogonyaev3 years ago

7 0

Answer:

Magdeburg hemispheres are two half-spheres of equal size. Placing them together traps air between them. This air is merely trapped, and not compressed, so the pressure inside is the same as the pressure of the atmosphere outside the spheres. The spheres thus pull apart with nearly no resistance.

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A 25 pF parallel-plate capacitor with an air gap between the plates is connected to a 100 V battery. A Teflon slab (dielectric c

adoni [48]

Answer:

The change in the charge on the positve plate when the Teflon is inserted is +2.5 nC.

Explanation:

It can be showed that the capacitance of a parallel-plate capacitor, can be expresssed as follows:

$C = \frac{\epsilon*A}{d}$

Where ε, is the dielectric constant of the material that fills the space between plates.
When this space is filled with air, ε= ε₀ = 8,85*10⁻¹² F/m.
At the same time, the capacitance of a capacitor, by definition, is as follows:

$C =\frac{Q}{V}$

If we insert a Teflon slab, in such a way that fills completely the gap between the plates, all other parameters being equal, if ε = 2*ε₀, this means that C₂ = 2* C₁. = 50 pF
As V₂=V₁ (due to the capacitor remains connected to the same battery) the charge must be the double, so Q₂ = 2* Q₁ = 5 nC.
So, the change in the charge of the positive plate is +2.5 nC.

3 0

3 years ago

What happens to the size of the image as the focal length is increased?

natta225 [31]

The parimiter expands

6 0

3 years ago

A transformer is to be used to provide power for a computer disk drive that needs 6.0 V (rms) instead of the 120 V (rms) from th

Ipatiy [6.2K]

Answer:

$N_{2}$ =20 turns

Explanation:

The given case is a step down transformer as we need to reduce 120 V to 6 V.

number of turns on primary coil N_{P}= 400

current delivered by secondary coil I_{S}= 500 mA

output voltage = 6 V (rms)

we know that

$I_{p}=\frac{V_{out}}{V_{in}\times I_{s}}$

putting values we get

$I_{p}=\frac{6}{120\times 0.5}$

$I_{p}= 0.1 A$

to calculate number of turns in secondary

$\frac{N_{2}}{400} =\frac{6}{120}$

therefore, $N_{2}$ =20 turns

5 0

3 years ago

Joan stirred a pot of hot soup with a metal spoon. after a minute or two, the handle of the spoon became too hot to hold. what k

natima [27]

When the metal spoon comes in contact with the hot soup, heat transfer from hot soup to the spoon because of difference in temperature of the two. The kind of heat transfer represented here is conduction. In conduction, heat is transferred from a region of higher temperature to a region of lower temperature when there is a physical contact between the two.

4 0

3 years ago

Which describes why people on earth can see light from the stars in the sky that are so far away?

Ugo [173]

Yes, C is correct. It self explains itself as we know light travels through a vacuum ( doesn't need a medium) and light is a type of electromagnetic wave.

7 0

3 years ago