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3 years ago

Which statement about an atom is correct?(1 point)

Physics

2 answers:

alexdok [17]3 years ago

5 0

Answer:

The electron has a negative charge and is found outside of the nucleus.

Explanation:

1.) Neutrons have no charge, not a negative charge.

2.) Neutrons are found inside the nucleus, not outside.

3.) Protons have a positive charge.

PSYCHO15rus [73]3 years ago

3 0

Answer:
the electron has a negative charge and is found outside of the nucleus
explanation:
neutron is neutral inside the nucleus
proton is positive inside the nucleus
electron is negative outside the nucleus

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An electric fan has the power output of 60W. How much work is done if the fan operates for 120s?

Digiron [165]

Since power = work done/time, 60= work done/120, work done = 120*60 = 7200. So,work done = 7200N (Newton).
I'm not sure if you're supposed to convert the seconds to time.

4 0

4 years ago

which part of the microscope will be used first to adjust the focus when starting with the lowest power lens?

noname [10]

The first part of the microscope that should first be used to adjust the focus when starting with the lowest power lens would be the coarse adjustment knob.

There are two knobs in a typical light microscope with which objects on slides can be brought into focus:

Coarse adjustment knob
Fine adjustment knob

The 2 knobs are used to adjust the stage to either bring it up towards the objective lens or down away from them. The coarse adjustment knob, however, moves the stage a considerable distance with each turn. The fine adjustment knob, on the other hand, only moves the stage very little with each turn.

The lowest power lenses are often short. Hence, using the coarse adjustment knob is ideal in order to quickly bring objects on slides into focus.

The fine adjustment knob comes highly recommended at high objectives because high objectives lenses are usually long and using the coarse adjustment knob can lead to a breakage of the slide by the lens.

More on bringing objects into focus on a microscope can be found here: brainly.com/question/24319677

7 0

3 years ago

A concrete highway is built of slabs 12 m long .How wide should be the expansion cracks between the slabs at 15 Celsius to preve

morpeh [17]

Answer:

$x=4.2\ mm$

Explanation:

Given:

length of the concrete slab, $l=12\ m$

temperature of observation, $T_o=15^{\circ}C$

we've the coefficient of linear expansion for concrete, $\alpha=10^{-5}\ ^{\circ}C^{-1}$

lower temperature limit, $T_l=-30^{\circ}C$

upper temperature limit, $T_u=50^{\circ}C$

Change in length due to temperature can be given as:

$\Delta l=l.\alpha.(T_u-T_l)$

$\Delta l=12\times 10^{-5}\times (50-(-30))$

$\Delta l=0.0096\ m=9.6\ mm$

Now at temperature 15°C:

$\Delta l'=12\times 10^{-5}\times (15-(-30))$

$\Delta l'=0.0054\ m=5.4\ mm$

Hence the expansion crack between the slabs at this temperature must be:

$x=\Delta l-\Delta l'$

$x=9.6-5.4$

$x=4.2\ mm$

3 0

3 years ago

A jet airplane is in level flight. The mass of the airplane is m=9010kg. The airplane travels at a constant speed around a circu

Lyrx [107]

Answer:

The magnitude of the lift force L = 92.12 kN

The required angle is ≅ 16.35°

Explanation:

From the given information:

mass of the airplane = 9010 kg

radius of the airplane R = 9.77 mi

period T = 0.129 hours = (0.129 × 3600) secs

= 464.4 secs

The angular speed can be determined by using the expression:

ω = 2π / T

ω = 2 π/ 464.4

ω = 0.01353 rad/sec

The direction $\theta = tan^{-1} ( \dfrac{\omega ^2 R}{g})$

$\theta = tan^{-1} ( \dfrac{0.01353 ^2 \times (9.77\times 1609)}{9.81})$

θ = 16.35°

The magnitude of the lift force L = mg ÷ Cos(θ)

L = (9010 × 9.81) ÷ Cos(16.35)

L = 88388.1 ÷ 0.9596

L = 92109.32 N

L = 92.12 kN

3 0

3 years ago

11. An example of a compound is A. salt B. salt water C. sodium D. soft drinks

katovenus [111]

Answer:

The correct answer is: A. salt

Explanation:

The salt corresponds to sodium chloride, whose chemical formula is NaCl. A compound is defined as that substance formed by a combination of 2 or more atoms.

8 0

3 years ago