Our bodies emit heat, and nerve endings in our skin can detect it.
Our eyes can detect visible light, but our bodies don't emit that.
Answer:
During convection, hot material expands & rises then moves to the side and cools & sinks. this circular pattern is called a convection current.
Explanation:
Convection is one of the three methods of transfer of heat. It occurs only in fluids (liquids or gases).
Convection occurs when there is a source of heat that heats a fluid, such as in a boiling pot of water. The water which is on the bottom of the pot becomes warmer before than the water at the top (because it is closer to the flame), and so it becomes less dense: for this reason, it expands and it becomes rising. On the contrary, the water on top is colder, so it is more dense and starts sinking, replacing the warmer water. As the new part of water gets warmer, it starts rising, and so the process is continuously repeated. This circular current is called convection current.
Answer:
(a) 6.567 * 10^15 rev/s or hertz
(b) 8.21 * 10^14 rev/s or hertz
Explanation:
Fn= 4π^2k^2e^4m * z^2/(h^3*n^3)
Where Fn is frequency at all levels of n.
Z = 1 (nucleus)
e = 1.6 * 10^-19c
m = 9.1 * 10^-31 kg
h = 6.62 * 10-34
K = 9 * 10^9 Nm2/c2
(a) for groundstate n = 1
Fn = 4 * π^2 * (9*10^9)^2*(1.6*10^-19)^4* (9.1 * 10^-31) * 1 / (6.62 * 10^-31)^3 = 6.567 * 10^15 rev/s
(b) first excited state
n = 1
We multiple the groundstate answer by 1/n^3
6.567 * 10^15 rev/s/ 2^3
F2 = 8.2 * 10^ 14 rev/s
Answer:
22.505 seconds
Explanation:
V =19.8m/s
V = a*to
t1 = 19.8/3.3
= 6seconds
Distance travelled during acceleration
= 1/2 x 3.3 x 6²
= 59.4m
X_total = x1 + x2
X2 = 373-59.4
X2 = 313.6m
t2 = x2/v
= 313.6/19.8
= 16.505
Total = 16.505 + 6
= 22.505 seconds
the minimum time in which an elevator can travel the 373 m from the ground floor is 22.505 seconds.
