Answer:
b) has leaves that are 8 -10 cm long
C.) a substance with a low ability to conduct energy
Explanation:
The statement that best defines insulators is that it is a substance that has low ability to conduct energy.
Insulators resist the movement of mostly electrical and thermal energy.
They have unique properties that makes them so.
- Insulators are substances that do not conduct heat and electricity.
- Both their solid and molten form lacks the capability of electrical and thermal conduction.
- Some substances can only conduct when molten or liquid.
- Conductors are materials that allows for the passage of electrical and heat energy.
- Most conductors are usually salts, ionic compounds and metals.
- Non-conductors like insulators are usually plastics and woods.
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Answer:
See below.
Step-by-step explanation:
<em>Method 1:
</em>
You know that oxygen is a <em>non-metal.
</em>
If the compound is ionic, the oxygen must be combined with a <em>metal</em>.
The Mg must be a metal.
<em>Method 2:</em>
In the formulas of ionic compounds, the positive ion (usually a metal) is written first.
Answer:
Explanation:
When an electron jumps from one energy level to a lower energy level some energy is released in the form of a photon.
The difference in energy between the two levels is the energy of the photon and that energy is related to the frequency of the photon by the Einstein - Planck equation:
Where,
- E = energy of the photon,
- h = 6.626×10⁻³⁴ J.s, Planck constant, and
- ν = frequency of the photon.
So, to find the frequency you must first find the energy.
The transition energy can be calculated using the formula:
Where E₀ = 13.6 eV ( 1 eV = 1.602×10⁻¹⁹ Joules) and n = 1,2,3,...
So, the transition energy between n = 4 and n = 3 will be:
- ΔE = - E₀ [ 1/4² - 1/3²] = - 13.6 eV [1/16 - 1/9] = 0.6611. . .eV
- ΔE = 1.602×10⁻¹⁹ Joules/eV × 0.6611... eV = 1.0591 ×10⁻¹⁹ Joules
Now you can use the Einstein - Planck equation:
- ν = 1.0591 ×10⁻¹⁹ J / 6.626×10⁻³⁴ J.s = 1.60×10¹⁴ s⁻¹ (rounded to 3 significant figures).
