Answer:
The correct option is: <u>B. 366 torr</u>
Explanation:
Given: <u>On the ground</u>- Initial Volume: V₁ = 8.00 m³, Initial Atmospheric Pressure: P₁= 768 torr;
<u>At 4200 m height</u>- Final Volume: V₂ = 16.80 m³, Final Atmospheric Pressure: P₂ = ?
Amount of gas: n, and Temperature: T = constant
<u>According to the Boyle's Law</u>, for a given amount of gas at constant temperature: P₁ V₁ = P₂ V₂
⇒ P₂ = P₁ V₁ ÷ V₂
⇒ P₂ = [(768 torr) × (8.00 m³)] ÷ (16.80 m³)
⇒ P₂ = 365.71 torr ≈ 366 torr
<u>Therefore, the final air pressure at 4200 m height: P₂ = 366 torr.</u>
Answer: The frequency of the wave is 0.5 hertz.
Explanation:

= Frequency of the wave
= speed of the light in m/s
= Wavelength of the wave.
Here in question we are given with speed of the infrared light. So, we will replace the value of speed of light(c) from the given value of the speed of the infrared light.
Speed of infrared light = 6 m/s

The frequency of the wave is 0.5 hertz.
Answer
:
Flammable substances
Explanation
:
<em>Flammable substances</em> will catch fire and continue to burn when they contact an ignition source like a spark or a flame.
For example, <em>methanol</em> is a flammable liquid.
A flammable solid may also catch fire through friction. <em>Matches</em> are flammable solids.