In series circuit, Req = R₁ + R₂ + R₃ + ···
In parallel circuit, 
<h3>Q7.</h3>
total resistance in the upper branch = R₂ + R₃ = R₂ + 2
R₂ + 2 = 12
R₂ = 10Ω
<h3>Q8.</h3>
Req = 1.7Ω
The efficiency of a light source is the percentage of its energy input that gets radiated as visible light if some of the blue light in an led is used to cause a fluorescent material to glow the overall efficiency of the LED decreases.
How efficient is LED?
Different wavelengths that correlate to different visible colours are used in LED light therapy. Various shades pierce the skin at different rates.
- Your skin's outermost layer is impacted by blue light.
- Yellow light is more enveloping.
- Red light penetrates your skin more deeply.
- The deepest penetrating light is near-infrared.
Different LED hues have various effects. For instance, according to experts red LED light therapy has the potential to reduce inflammation and boost collagen formation, which declines with age and is crucial for maintaining youthful-looking skin.
Acne-causing bacteria may be destroyed by a blue LED light therapy (P. acnes).
Hence the answer is the overall efficiency of the LED decreases.
Learn more about wavelength here,
brainly.com/question/1263539
# SPJ4
Answer:
Selenium dichloride
Explanation:
Selenium (Se) and Chlorine (Cl) are both elements capable of combining together to form a compound with the chemical formula; SeCl2. Since the chlorine atom is more electronegative than selenium atom, the chlorine pulls more electrons towards itself to form an IONIC bond.
The SeCl2 compound formed is called Selenium dichloride as two atoms of Chlorine are needed to combine with one atom of Selenium to form the compound.
Gravitational potential energy, relative to some level =
(mass of the object)
times
(height above the reference level)
times
(acceleration due to gravity) .
