Answer:
When the metal wire in an incandescent lightbulb glows when the light is switched on and stops glowing when it is switched off, this is an example of resistance, which provides light and heat.
Explanation:
To solve this problem we will apply the concepts related to the calculation of the speed of sound, the calculation of the Mach number and finally the calculation of the temperature at the front stagnation point. We will calculate the speed in international units as well as the temperature. With these values we will calculate the speed of the sound and the number of Mach. Finally we will calculate the temperature at the front stagnation point.
The altitude is,

And the velocity can be written as,


From the properties of standard atmosphere at altitude z = 20km temperature is



Velocity of sound at this altitude is



Then the Mach number



So front stagnation temperature



Therefore the temperature at its front stagnation point is 689.87K
Answer:
The colour of visible light depends on its wavelength. These wavelengths range from 700 nm at the red end of the spectrum to 400 nm at the violet end. Visible light waves are the only electromagnetic waves we can
Explanation:
Answer:
D) a Battery
Explanation:
The best real-life example of direct current is a battery. Batteries have positive and negative terminals on a battery, the electrons in the wires will begin to flow to produce a current.
No, the earth is a sphere, and yes.