Answer:
the stars which are red in color are cool.
Explanation:
The stars which has reddish color are cool in nature while those stars which has white and blue in color are very hot in nature. The stars change its color when they becomes hotter , first the star color reddish when they are cool but with increasing temperature it changes the color from reddish to orange then yellow. After yellow it turns green and finally get blue color when the stars are very very hot.
Concept:
Frequency- It is defined as the number of oscillations occur in one second.
Its SI unit is Hertz (Hz)
Given: Produced sound vibrations is 18,500 cycles in 0.75 seconds
∵ In 0.75 second, produced sound has oscillations = 18,500 cycles
∴ In 1.0 second, produced sound has oscillations = (18,500 ÷ 0.75) Hz
The frequency of the sound will be ≈ 24,667 Hz
From the study of the given graph, only the animals (c) Cats, (b) Moths and (a) Bats can hear the produced sound because their upper audible frequency range is greater than 24,667 Hz.
Answer:
a)
, b) 
Explanation:
a) According to the First Law of Thermodinamics, the system is not reporting any work, mass or heat interactions. Besides, let consider that such box is rigid and, therefore, heat contained inside is the consequence of internal energy.

The internal energy for a monoatomic ideal gas is:

Let assume that cubical box contains just one kilomole of monoatomic gas. Then, the temperature is determined from the Equation of State for Ideal Gases:



The thermal energy contained by the gas is:


b) The physical model for the cat is constructed from Work-Energy Theorem:

The speed of the cat is obtained by isolating the respective variable and the replacement of every known variable by numerical values:



X ray is one of the electromagnetic waves.
As per Clark Maxwell's electromagnetic theory, all the electromagnetic waves move with the velocity of light i.e c= 3×10^8 m/s
In case of electromagnetic waves,the electric field and magnetic field are perpendicular to each other as well as perpendicular to the direction of propagation.The electromagnetic waves exhibit the property of polarisation. Hence they are transverse in nature.
Hence the best statements about X- ray will be-
1- X -rays are electromagnetic waves
2-X-rays are transverse transverse waves
3- X- rays travel at the speed of light.
Answer:blocking all solar radiation
Explanation:
google has it