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charle [14.2K]
3 years ago
6

What is being described in the following definition: An opening in the floor, platform, or pavement that measures 12 inches or m

ore, and through which persons may fall.
A.
Floor Hole

B.
Floor Opening

C.
Wall Opening

D.
Railing
Physics
1 answer:
azamat3 years ago
3 0
Answer is Floor Opening
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Whiat is quantum numbers describes the size and energy of an orbital?
Levart [38]

Answer:

The answer is the principal Quantum number (n)

Explanation:

The principal quantum number is one of the four quantum numbers associated with an atom.

It is denoted by a number n=1,2,3,4 etc

It tells both size (directly) and energy (indirectly) of an orbital.

When n=1 means it is the closest to the nucleus and is the smallest orbital and with increase in principal quantum number, it depicts that size of the orbital is increasing.

It tells the energy of the orbital as well as smaller number means less distance from nucleus and having less energy. Since electrons requires to absorb energy to jump into higher orbitals making n=2,3,4 etc. Thus electrons in the orbitals with higher n number indicates higher energy orbitals.

7 0
3 years ago
A machine can never be 100% efficient because some work is always lost due to what?
katrin [286]

A machine can never be 100% efficient because some work is always lost due to the lack of materials or equipment that would convert work by 100%. It follows the second law of entropy. The ideal engine is known as Carnot’s engine having a 100% efficiency. So far, no engine has ever gotten to 100%.

8 0
3 years ago
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Which change indicates that the universe is expanding?
Aleonysh [2.5K]
Red shift of distant galaxies
5 0
3 years ago
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A solid conducting sphere of radius 2 cm has a charge of 8microCoulomb. A conducting spherical shell of inner radius 4 cm andout
nika2105 [10]

Answer:

C) 7.35*10⁶ N/C radially outward

Explanation:

  • If we apply the Gauss'law, to a spherical gaussian surface with radius r=7 cm, due to the symmetry, the electric field must be normal to the surface, and equal at all points along it.
  • So, we can write the following equation:

       E*A = \frac{Q_{enc} }{\epsilon_{0}} (1)

  • As the electric field must be zero inside the conducting spherical shell, this means that the charge enclosed by a spherical gaussian surface of a radius between 4 and 5 cm, must be zero too.
  • So, the +8 μC charge of  the solid conducting sphere of radius 2cm, must be compensated by an equal and opposite charge on the inner surface of the conducting shell of total charge -4 μC.
  • So, on the outer surface of the shell there must be a charge that be the difference between them:

        Q_{enc} = - 4e-6 C - (-8e-6 C) = + 4 e-6 C

  • Replacing in (1) A = 4*π*ε₀, and Qenc = +4 μC, we can find the value of E, as follows:

      E = \frac{1}{4*\pi*\epsilon_{0} } *\frac{Q_{enc} }{r^{2} } = \frac{9e9 N*m2/C2*4e-6C}{(0.07m)^{2} } = 7.35e6 N/C

  • As the charge that produces this electric field is positive, and the electric field has the same direction as the one taken by a positive test charge under the influence of this field, the direction of the field is radially outward, away from the positive charge.
6 0
3 years ago
Determine the COP. for this thermodynamic refrigerator
Dennis_Churaev [7]

Answer:

Explanation:

The efficiency of a refrigerator is defined in the terms of coefficient of performance (COP).

The ratio of amount of heat in cold reservoir to the work done is termed as the COP.

COP = QL / W

COP = T2 / (T1 - T2)

Where, T1 be the temperature of hot reservoir, T2 be the temperature of cold reservoir.

6 0
3 years ago
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