Answer: A and B
Explanation:
Electromagnetic radiations are examples of electromagnetic waves with increasing frequency and decreasing wavelength in the following order radiowaves - infrared waves - visible lights - ultraviolet rays- x-rays - gamma rays.
They did not require material medium for their propagation.
The statement above shows that EM radiations possesses different wavelengths and frequency.
Entropy is the measure of the amount of disordered in a system.
<u>Explanation:</u>
In 1850, Entropy introduction by the German physicist Rudolf Clausius refers a measurement of the system's thermal energy in unit temperature. It is not for useful work because the work originates from ordered molecular motions. And, this also measures the molecular disturbance or randomness of the system.
The concept behind this provides deep view into spontaneous changes in many everyday phenomena’s. The idea of entropy is a mathematical way of coding an intuitive idea whose processes are impossible, and not violate the basic principle of energy conservation.
Answer:
B) The cosmic background radiation is expected to contain spectral lines of hydrogen and helium, and it does.
Explanation:
I beleive she isnt doing any work due to holding the box motionless, you must be exerting a force in the direction of the box motion. If she is just standing there holding the box their isn't no work becuase no distance has been covered. work = force = distance.