Answer:
Explanation:
Force per unit length between two cables at distance d carrying current I₁ and I₂ can be given by the following expression .
F = 10⁻⁷ x 2I₁ I₂ / d
I₁ = I₂ = 15000 A
F = 10⁻⁷ x 2I₁ I₂ / d
= 10⁻⁷ x 2 x 15000² / 4.5 x 10⁻³ m
= 10000 N .
It will be repelling force ie they will repel each other because current is in opposite direction .
No , we should not be concerned about mechanical strength because force does not depend on it .
Answer:
Rotational kinetic energy = 0.099 J
Translational kinetic energy = 200 J
The moment of inertia of a solid sphere is 
.
Explanation:
Rotational kinetic energy is given by
where <em>I</em> is the moment of inertia and <em>ω</em> is the angular speed.
For a solid sphere,
where <em>m</em> is its mass and <em>r</em> is its radius.
From the question,
<em>ω</em> = 49 rad/s
<em>m</em> = 0.15 kg
<em>r</em> = 3.7 cm = 0.037 m
Translational kinetic energy is given by
where <em>v</em> is the linear speed.
Answer:
C) A low-density, cool gas in isolation creates a continuous spectrum.
Explanation:
Kirchhoff’s laws established that:
- A solid, liquid or dense incandescent gas emits a continuous spectrum.
- A hot and diffuse gas produces bright spectral lines (emission lines).
- A gas of lower temperature against a source of continuum spectrum, produces dark spectral lines (absorption lines) superposed in the continuum spectrum.
Stars are perfect examples for Kirchhoff’s laws. Since in the case of the stars, the photons that are received are not directly from the nucleus, but those that have traveled hundreds of thousands of years to reach the stellar atmosphere. Due to the stars are not at homogeneous temperature, density and pressure, but have gradients in different layers because of the nuclear reactions, superficial gravity or to its constant exchange of heat with its surroundings in an attempt to reach the thermodynamic equilibrium, the continuum observed in the stellar spectra comes from the inner layer of the photosphere, while absorption lines are formed in the outer layer of the photosphere and the stellar atmosphere. More accurately, a photon of the inner layer of the photosphere will be absorbed by an electron of an atom or ion that is in the outer layer, generating an electronic transition¹, the electron, upon returning to its base state will emit a photon or a series of photons that will not necessarily go in the same direction of the incident photon, creating an absorption line in the stellar spectrum.
On the other hand, in the case where the stars have surrounding material (diffuse gas), the atoms, molecules or ions in the medium are excited by the radiation that comes from the stellar atmosphere, thus producing an emission spectrum.
Key terms:
¹Electronic transition: When an electron passes from one energy level to another, either for the emission or absorption of a photon.
Answer:
When the sun shines onto a solar panel, energy from the sunlight is absorbed by the PV cells in the panel. This energy creates electrical charges that move in response to an internal electrical field in the cell, causing electricity to flow.
