Answer:
C. Sunlight to electricity
Explanation:
Photo voltaic cells covert sunlight to the electricity. It absorbs the light from the sun and use that sunlight to create electric current. The number of photo voltaic cells are connected together in a solar panel to generate enough electricity to power up a home.
Answer:
N = 3032 turns
Explanation:
The magnetic field produced by a solenoid is described by
B = μ₀ n I
Where is the permittivity in a vacuum with a value of 4π 10⁻⁷ N /A², n is the turn density and I the current
Let's apply this equation to the problem, the turn density is the number of turns per unit length, in this case it is the same magnet length
L = 8 cm = 0.08 m
Let's calculate
B = μ₀ N/L I
N = B L / μ₀ I
N = 0.10 0.08 / (4π 10⁻⁷ 2.1)
N = 3,032 103 turns
Answer: i think c
Explanation:QA: “What is ordinary glass made of ?”
Glass is mostly silica, or silicon dioxide, present as quartz in many types of sand. Pure silica forms a highly transparent glass, but has a very high melting or softening temperature, around 1700°C. Even at such high temperatures it is highly viscous and difficult to work. Its use is largely confined to applications requiring high transparency to ultra-violet and infra-red radiation, stability at elevated temperatures or low thermal expansion coefficient.
“Ordinary glass” windows and drinking vessels are typically made from soda-lime glass, containing silica with around 25% sodium, calcium and other oxides, which together reduce the softening temperature to roughly 500–600°C
Answer:
8. 2.75·10^-4 s^-1
9. No, too much of the carbon-14 would have decayed for radiation to be detected.
Explanation:
8. The half-life of 42 minutes is 2520 seconds, so you have ...
1/2 = e^(-λt) = e^(-(2520 s)λ)
ln(1/2) = -(2520 s)λ
-ln(1/2)/(2520 s) = λ ≈ 2.75×10^-4 s^-1
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9. Reference material on carbon-14 dating suggests the method is not useful for time periods greater than about 50,000 years. The half-life of C-14 is about 5730 years, so at 65 million years, about ...
6.5·10^7/5.73·10^3 ≈ 11344
half-lives will have passed. Whatever carbon 14 may have existed at the time will have decayed completely to nothing after that many half-lives.
