A wave produced by a door bell?
There is a sound wave yes.
Answer:
Holaaaaaaaaaaa..............................
Explanation:
Answer: 0.258
Explanation:
The resistance
of a wire is calculated by the following formula:
(1)
Where:
is the resistivity of the material the wire is made of. For aluminium is
and for copper is 
is the length of the wire, which in the case of aluminium is
, and in the case of copper is 
is the transversal area of the wire. In this case is a circumference for both wires, so we will use the formula of the area of the circumference:
(2) Where
is the diameter of the circumference.
For aluminium wire the diameter is
and for copper is 
So, in this problem we have two transversal areas:
<u>For aluminium:</u>

(3)
<u>For copper:</u>

(4)
Now we have to calculate the resistance for each wire:
<u>Aluminium wire:</u>
(5)
(6) Resistance of aluminium wire
<u>Copper wire:</u>
(6)
(7) Resistance of copper wire
At this point we are able to calculate the ratio of the resistance of both wires:
(8)
(9)
Finally:
This is the ratio
Answer:
3. relatively high temperature, about 10,000 K, so that significant numbers of electrons are excited from the ground state, n = 1, to the first excited state, n = 2, but not too many of them have been ejected completely from the atoms
Explanation:
If hydrogen absorption lines are very strong in the visible spectrum of a particular star that means the population of electron in n = 2 is very high so on being exited they absorb radiation in Balmer series and give rise to absorption spectrum. The average temperature required to excite electron in hydrogen atom from n=1 to n = 2 is 10000K .