Answer : The correct answer is option A : Supergiants
Explanation :
In the above graph absolute brightness is marked on y-axis and surface temperature is marked on x-axis.
To find out what type of star has an absolute brightness of 5 and a surface temperature around 3,000 °C, we will draw a straight line from x axis which represents a temperature of 3,000 °C and another straight line from y-axis which represents absolute brightness of 5.
From the attached graph we can see that these 2 lines meet in the region shown by Supergiants
Therefore we can say that, Supergiants has an absolute brightness of 5 and a surface temperature around 3,000 °C
Answer:- b. +3
Explanations:- Charge of a metal ion is equal to the number of valence electrons it has as it loses these electrons to have its nearest noble gas like electron configuration.
Al has 3 valence electrons and being a metal it loses all of these and so the charge of Al ion is +3. It could be shown as:
So, the right choice is b. 3+.
The missing question is:
<em>What is the percent efficiency of the laser in converting electrical power to light?</em>
The percent efficiency of the laser that consumes 130.0 Watt of electrical power and produces a stream of 2.67 × 10¹⁹ 1017 nm photons per second, is 1.34%.
A particular laser consumes 130.0 Watt (P) of electrical power. The energy input (Ei) in 1 second (t) is:
The laser produced photons with a wavelength (λ) of 1017 nm. We can calculate the energy (E) of each photon using the Planck-Einstein's relation.
where,
The energy of 1 photon is 6.52 × 10⁻²⁰ J. The energy of 2.67 × 10¹⁹ photons (Energy output = Eo) is:
The percent efficiency of the laser is the ratio of the energy output to the energy input, times 100.
The percent efficiency of the laser that consumes 130.0 Watt of electrical power and produces a stream of 2.67 × 10¹⁹ 1017 nm photons per second, is 1.34%.
You can learn more about lasers here: brainly.com/question/4869798