Answer:
Helium
Explanation:
Helium is the least reactive element, since it is a noble gas with the smallest amount of valence rings.
Answer:
= 1.7 cm
Explanation:
The magnification of the compound microscope is given by the product of the magnification of each lens
M = M₀ 
M = - L/f₀ 25/
Where f₀ and are the focal lengths of the lens and eyepiece, respectively, all values in centimeters
In this exercise they give us the magnification (M = 400X), the focal length of the lens (f₀ = 0.6 cm), the distance of the tube (L = 16 cm), let's look for the focal length of the eyepiece ()
= - L / f₀ 25 / M
Let's calculate
= - 16 / 0.6 25 / (-400)
= 1.67 cm
The minus sign in the magnification is because the image is inverted.
= 1.7 cm
The time for the echo to return is directly proportional to the distance. vw = fλ. In a given medium under fixed conditions, vw is constant, so that there is a relationship between f and λ; the higher the frequency, the smaller the wavelength.
electromagnetic spectrum is consisting of many frequency range which is from gamma rays to radio waves
they are of various wavelength and different energy levels
minimum wavelength will occurs at Gamma rays
and maximum wavelength at Radio waves
the list of increasing order of wavelength is as following
Gamma rays < X rays < Ultraviolet < Visible Light < Infrared Waves < Radio Waves
so least to maximum order is
1. Gamma rays
2. X rays
3 Ultraviolet
4 Visible light
5 Infrared waves
6 Radio waves
Group 17 (VII) (halogens)
