I need some help w/ this:
1 answer:
Answer:
The velocity of the police car is, v = 17.798 m/s
Explanation:
Given data,
The actual frequency of the siren, f = 2010 Hz
The observed frequency of siren is, f' = 2120 Hz
The velocity of the observer, v' = 0 m/s
The velocity of the source, v = ?
The formula for Doppler effect,
Where,
V - velocity of sound waves in air.
Substituting the given values,
v = 17.798 m/s
Hence, the velocity of the police car is, v = 17.798 m/s
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Answer:
1660 V
Explanation:
Resistance should be determined and then voltage drop across the power line can be determined.
R = ρ L /A
Here ρ = Resistivity of aluminum =
L = length = 32 km = 32,000 m
Area of cross section = A = π r² = π (0.027/2)² = 0.00057255 m²
Resistance = R =
( (32,000)/(0.00057255) = 1.5090 Ohms.
Voltage drop = V = I R = (1100)(1.5090) = 1659.9 V.
(If resistivity value is different, then the resistance will be different and hence final answer for voltage will also vary ).
Answer:
Explanation:
For n-=1 state hydrogen energy level is split into three componets in the presence of external magnetic field. The energies are,
,
,
Here, E is the energy in the absence of electric field.
And
are the highest and the lowest energies.
The difference of these energies
is known as Bohr's magneton.
B=2.5 T,
Therefore,
Now,
Therefore, the energy difference between highest and lowest energy levels in presence of magnetic field is