Answer:
(a) ![\lambda=0.032\ m](https://tex.z-dn.net/?f=%5Clambda%3D0.032%5C%20m)
(b) v = 1064 m/s
Explanation:
(a) Frequency of electromagnetic wave, ![f=9.35\ GHz=9.35\times 10^9\ Hz](https://tex.z-dn.net/?f=f%3D9.35%5C%20GHz%3D9.35%5Ctimes%2010%5E9%5C%20Hz)
Let
is the wavelength of electromagnetic wave. It can be calculated as :
![c=f\lambda](https://tex.z-dn.net/?f=c%3Df%5Clambda)
![\lambda=\dfrac{c}{f}](https://tex.z-dn.net/?f=%5Clambda%3D%5Cdfrac%7Bc%7D%7Bf%7D)
![\lambda=\dfrac{3\times 10^8\ m/s}{9.35\times 10^9\ Hz}](https://tex.z-dn.net/?f=%5Clambda%3D%5Cdfrac%7B3%5Ctimes%2010%5E8%5C%20m%2Fs%7D%7B9.35%5Ctimes%2010%5E9%5C%20Hz%7D)
![\lambda=0.032\ m](https://tex.z-dn.net/?f=%5Clambda%3D0.032%5C%20m)
(b) Frequency of medium, f = 532 Hz
Wavelength, ![\lambda=2\ m](https://tex.z-dn.net/?f=%5Clambda%3D2%5C%20m)
Let v is the speed of sound wave in an unknown fluid. Using the relation as :
![v=f\lambda](https://tex.z-dn.net/?f=v%3Df%5Clambda)
![v=532\times 2](https://tex.z-dn.net/?f=v%3D532%5Ctimes%202)
v = 1064 m/s
Hence, this is the required solution.
Using the wavelength expressions, such as the distance between two peaks of a wave, that of the frequency as a function of the speed and the wavelength, such as the period inversely proportional to the frequency we have to for the first question
the wavelength is the distance between the two ridges that is
![\lambda = 0.8m](https://tex.z-dn.net/?f=%5Clambda%20%3D%200.8m)
For the second question the frequency is determined as the rate of change of the velocity versus the wavelength, that is
![f = \frac{v}{\lambda}](https://tex.z-dn.net/?f=f%20%3D%20%5Cfrac%7Bv%7D%7B%5Clambda%7D)
![f = \frac{2.2}{0.8}](https://tex.z-dn.net/?f=f%20%3D%20%5Cfrac%7B2.2%7D%7B0.8%7D)
![f= 2.75Hz \approx 2.8Hz](https://tex.z-dn.net/?f=f%3D%202.75Hz%20%5Capprox%202.8Hz)
For the third question the period is inversely proportional to the frequency, therefore
![T = \frac{1}{f}](https://tex.z-dn.net/?f=T%20%3D%20%5Cfrac%7B1%7D%7Bf%7D)
![T = \frac{1}{2.8}](https://tex.z-dn.net/?f=T%20%3D%20%5Cfrac%7B1%7D%7B2.8%7D)
![T = 0.36s](https://tex.z-dn.net/?f=T%20%3D%200.36s)
Electric Heating systems use electricity as a source of heat.
<u>Explanation:
</u>
Each heater consists of an electric resistor, which the heating element in it. The process involved is Joule Heating. It is the phenomenon in which, passage of electric current produces heat. Heat is generated when the electrons from the current and the positive ions of the conductor start interaction.
The presence of voltage difference makes an electric fields, which in turn accelerates the charges present in the conductors. When they collide with ions of conductor, heat gets generated, and emitted out, which we use for heating purposes.
Answer:
A. Theory
Explanation:
The scientific method consists of following six steps:
1. Observation 4. Prediction
2. Experiment 5. Hypothesis
3. Law 6. Theory
1. Observation:
Observations are taken carefully and systematically. In this way all possible information is gathered
about physical phenomenon.
2. Hypothesis:
Keeping these observations in mind scientist makes some postulates to explain the phenomenon. These postulates are called hypothesis.
3. Theory:
Scientist design a theory on the basis of hypothesis and gives an elaborated explanation about the phenomenon.
4. Prediction:
Sometimes a scientist presents a theory on the basis rational reasoning and predicts some phenomenon to take place under certain conditions.
5. Experiment:
The theory or prediction is tested by experiments. If the theoretical and experimental results agree with each other, the theory is accepted otherwise it is discarded.
6. Law:
A theory which is tested again and again and found to fit the facts and from which valid predictions are maybe made are known as ‘Law’.
So it is clear from the given explanation that the term, which best describes the phrase ""a description of what happens in nature" is:
<u>A. Theory</u>