This
is
true
Electromagnetic waves travel fastest through vacuum
Gamma radiation could be used to sterilize plastic petri plates in a plastic wrapper.
Answer: Option E
<u>Explanation:
</u>
It is known that radioactive radiations have greater ionizing powers compared to other electromagnetic radiations. Among the radioactive radiations, gamma rays are the most ionizing radiation.
So they are widely used in sterilizing process. As the penetration power of gamma is more compared to alpha and beta, in order to kill microorganisms gamma radiations are used.
When plastic petri plates wrapped with plastic are bombarded or sterilizing with gamma rays, the rays will ionise the micro-organism. Thus mutilating their DNA and preventing their reproduction.
<u>Answer:</u>
<em>The average speed of the car is 66.9 km/h</em>
<u>Explanation:</u>
Here distance covered with the speed <em>57 km/h=7 km </em>
distance covered with the speed of <em>81 km/h=7 km</em>
<em>Average speed is equal to the ratio of total distance to the total time.
</em>
<em>total distance= 7 + 7= 14 km </em>
<em>
</em>
<em>time taken to cover the first 7 km= 7/57 h </em>
<em>time taken to cover the second part of the journey = 7/81 h
</em>
<em>average speed =
</em>
<u><em>Shortcut:
</em></u>
<em>When equal distances are covered with different speeds average speed=2 ab/(a+b) where a and b are the variable speeds in the phases.
</em>
Answer: <u>Trough </u> can lift the 403,342 ton pioneering spirit crane vessel 10 meters in 30 seconds as if it was a cork. This about 36 GJ if work and 1 GW of power.
Explanation:
Trough is the correct answer because<u> pioneering scale usually abide only on trough not on the other given options</u>. A long , narrow depression between the waves or ridges is known as a trough. The lower point in the period is the trough.
- <u>Speed -:</u> Speed is the distance per unit of time that a body moves. It's a quantity scaler that has just magnitude.
- <u>Wave energy -: </u>The transmission and capture of energy by ocean surface waves is wave energy (or wave power). The energy collected is then used for all sorts of useful work, including the generation of electricity, water desalination, and water pumping.
- <u>Crest -</u>: A crest point within a cycle on a wave with the highest value of upward displacement. A crest is a point on a surface wave where the medium's displacement is at its height.
- <u>Amplitude -:</u> The maximum displacement or distance measured from its equilibrium position, moved by a point on a vibrating body or wave, is called amplitude. It is equal to half of the vibration path's length.
- <u>Period-</u>: The duration T is the time needed to pass a given point for one complete cycle of vibration. The wave length decreases as the frequency of a wave increases.
- <u>Wavelength-:</u> The distance between two successive crests or troughs of a wave can be described as the wavelength. The frequency is inversely proportional to the wavelength. This implies that the longer the wavelength, the smaller the frequency. Similarly, the shorter the wavelength, the higher the frequency would be.
- <u>Frequency</u> -: Frequency defines the number of waves in a given amount of time that travel through a fixed location. In the Hertz unit, frequency is normally measured.
- <u>Information</u> -: A piece of data is a basic fact about the identity or properties of an object, i.e. a portion of its example.
- <u>Milli -</u>: Milli is known as a merged form meaning 'thousand' (millipede) used in the metric system for unit names equal to one thousandth of the base unit (millimeter) given.
Hence , the answer is <u>TROUGH.</u>
Newton's law of conservation states that energy of an isolated system remains a constant. It can neither be created nor destroyed but can be transformed from one form to the other.
Implying the above law of conservation of energy in the case of pendulum we can conclude that at the bottom of the swing the entire potential energy gets converted to kinetic energy. Also the potential energy is zero at this point.
Mathematically also potential energy is represented as
Potential energy= mgh
Where m is the mass of the pendulum.
g is the acceleration due to gravity
h is the height from the bottom z the ground.
At the bottom of the swing,the height is zero, hence the potential energy is also zero.
The kinetic energy is represented mathematically as
Kinetic energy= 1/2 mv^2
Where m is the mass of the pendulum
v is the velocity of the pendulum
At the bottom the pendulum has the maximum velocity. Hence the kinetic energy is maximum at the bottom.
Energy can neither be created e destroyed. It can only be transferred from one form to another. Implying this law and the above explainations we conclude that at the bottom of the pendulum,the potential energy=0 and the kinetic energy=294J as the entire potential energy is converted to kinetic energy at the bottom.