Intensive properties are not dependent on the amount of substance. Melting point, pressure, temperature, and density are some examples of intensive properties. Therefore, volume of a substance is not an example of an intensive property, rather, it is an extensive property which depends on the amount of substance. Some other examples of extensive properties include weight, energy, and electric charge.

Photons are fundamental particles that make up electromagnetic waves (light). The key aspect of photon is that it has very high speed  and no mass; therefore, mass for photons is always zero.

Electromagnetic spectrum is a spectrum of different types of light. Each type of electromagnetic wave differs from one another based on the frequency and wavelength; however, the speed of every electromagnetic wave in air is . The wave equation relates the speed of an electromagnetic to its wavelength and frequency as follows.

Here,  is speed of light,  is wavelength, and  is frequency. Since  is always constant, wavelength and frequency are inversely proportional to each other. This means that if the wavelength increases the frequency decreases.

To solve this question, we need to use the equation relating energy of a wave to its wavelength.

Here,  is the energy,  is Planck’s constant,  is speed of light (for us it’s always ), and  is the wavelength (in meters). The energy of the ultraviolet rays is

If we look at the electromagnetic spectrum we will notice that the wavelength of radio waves is a lot higher than ultraviolet rays. Since energy is inversely proportional to wavelength we can conclude that the energy of radio waves is lower than ultraviolet's. The only answer choice with an energy lower than ultraviolet rays energy is 1.24neV.

Emission is the process of releasing (or emitting) photons from an atom whereas absorption is the process of absorbing photons. After emission, the atom releases energy (in the form of photons) and goes to a lower energy state. In absorption, however, the atom absorbs energy and goes to a higher energy state. Recall that lower energy always means more stable; therefore, after emission, an atom or molecule goes to a more stable state whereas after absorption it goes to a less stable state.

, where  is the speed of light,  is the wavelength, and  is frequency.

, where  is the speed of light,  is the wavelength, and  is frequency.

Amplitude of a wave is defined as the maximum peak of oscillation or vibration. Recall that frequency, wavelength, and speed are not dependent on the amplitude and are calculated using the wave equation:

Here,  is the speed of the wave (which is the speed of light for electromagnetic waves),  is the frequency, and  is the wavelength. Amplitude of a wave is not present in this equation and, therefore, cannot be used to determine relative values of frequency, wavelength, and speed.

The phenomenon described in this question is called redshift and blueshift. All stars emit electromagnetic waves. The perceived wavelength of these waves depends on the relative motion of the object. If an object is approaching the observer (in this case, the earth) then the apparent wavelength of emitted waves decreases whereas if the object moves away then the apparent wavelength increases. This is called the Doppler effect.

To answer this question, we need to know the relative wavelengths of blue and red light. Blue light has wavelength between  whereas red light has wavelength between . The question states that star A appears red and star B appears blue. Since red has the higher wavelength, star A is going away from the earth. Similarly, since blue has a lower wavelength, star B is approaching earth.

Recall that lower wavelength means higher frequency; therefore, blue has the higher frequency.

To solve this question, we need to first recall the electromagnetic spectrum. Microwaves have very large wavelengths. They are found between visible light and radio waves. Ultraviolet, on the other hand, is found below visible light; therefore, ultraviolet rays have smaller wavelength than microwaves.

To solve for energy we need to use the following equation.

Here,  is the energy,  is Planck’s constant,  is speed of light, and  is wavelength. Since energy is inversely proportional to wavelength, higher wavelengths will lead to lower energy. This means that microwaves will have lower energy than ultraviolet rays.

Gamma rays have the lowest wavelength and highest energy whereas radio waves typically have the highest wavelength and lowest energy.