302
324
280
The speed of sound varies in different mediums. In Physics, the speed of sound in air at 0°C is about 331.5 m/s, while in iron it's about 5130 m/s. If a train is 100 km away, the sound travelling through the iron rails would reach you approximately 282 seconds sooner than the sound through the air.
In Physics, the speed at which sound travels depends on the medium through which it's travelling. The speed of sound in air at 0°C is approximately 331.5 m/s. On the other hand, the speed of sound in iron is about 5130 m/s.
To determine how much sooner you would hear the train, we need to calculate the difference in time it takes for the sound to travel through these two mediums.
When the train is 100 km away, we get the following:
The difference is, therefore, approximately: 301.66 - 19.49 = 282.17 seconds. Thus, the sound will reach you 282 seconds sooner if you listen to the rails rather than the air.
#SPJ12
Answer:
An infinite temperature
Explanation:
The efficiency of an engine is defined as:
where
is the temperature at which heat enters the engine
is the temperature of the environment, to which the engine exhausts heat
From the formula, we see that for an engine to be 100% efficient, the fraction
must be equal to zero. Since the value of is never zero (the temperature is expressed in Kelvin, and the temperature of the environment can never be exactly 0 K), the only possibility for that to occur is that the temperature at which heat enters the engine () is infinite, so that this fraction becomes zero and the efficiency becomes 1.
How much total energy does this truck put out?
A. 50 J
B. 250 J
C. 400 J
D. 800 J
B) because electromagnetic waves transmit energy without compressing the particles of the medium
C) because electromagnetic waves generate their own particles for compression and use these for movement
D) because electromagnetic waves move in two-dimensional space, the particles of mediums exist in 3-D space
Answer:
B) because electromagnetic waves transmit energy without compressing the particles of the medium
Explanation:
Electromagnetic waves are the combination of electric and magnetic field which will oscillate perpendicular to each other. And the propagation of wave here is perpendicular to both electric and magnetic field.
So here in this type of wave propagation we do not require any medium as this is propagation of electric and magnetic field.
So here no need of compression or rarefaction of medium molecules and hence it do not need any medium to travel
so here correct answer is
B) because electromagnetic waves transmit energy without compressing the particles of the medium
Importanceofozonelayer:
Explanation:
Formationofozonelayer:ozone at the higher level of the atmosphere is a product of UV radiations acting on oxygen O2 molecule. The higher energy UV radiations split apart some molecular oxygen( O2) into free oxygen (O) atoms.
Depletionodozonelayer:The amount of ozone in the atmosphere began to drop sharply in the 1980's . This decrease has been linked to synthetic chemicals like cholorofluorocarbons ( CFC's ) which are used as refrigerants and in fire extinguishers.