Answer:Simple Covalent substance
Explanation:Simple covalent substance describes a substance that has a low melting point and poor electrical conductivity because:
(1)melting point :For the covalent bond and intermolecular force that are present in a simple covalent substance,energy is needed to break the forces of attraction present. In the simple covalent substance, little energy is needed because the intermolecular forces present are broken because they are weaker compared to the covalent bond present.
Therefore, when simple covalent substance melts,only the intermolecular forces are broken leaving only the covalent bond in the substance.
(2) poor conductivity: for a substance to conduct electricity,it must have charged particles which are free to move to and fro.
But in the simple covalent substance,there are no charged particles that can be separated due to the covalent bond present in simple covalent substance.
Explanation:
a) The Earth makes 1 rotation in 24 hours. In seconds:
24 hr × (3600 s / hr) = 86400 s
b) 1 rotation is 2π radians. So the angular velocity is:
2π rad / 86400 s = 7.27×10⁻⁵ rad/s
c) The earth's linear velocity is the angular velocity times the radius:
40075 km × 7.27×10⁻⁵ rad/s = 2.91 km/s
Complete Question
You are performing a double slit experiment very similar to the one from DL by shining a laser on two nattow slits spaced
meters apart. However, by placing a piece of crystal in one of the slits, you are able to make it so that the rays of light that travel through the two slits are Ï out of phase with each other (that is to say, Ao,- ). If you observe that on a screen placed 4 meters from the two slits that the distance between the bright spot closest to center of the pattern is 1.5 cm, what is the wavelength of the laser?
Answer:
The wavelength is 
Explanation:
From the question we are told that
The distance of slit separation is
The distance of the screen is 
The distance between the bright spot closest to the center of the interference is 
Generally the width of the central maximum fringe produced is mathematically represented as

=> 
=> 
=> 
Answer:
the answer is ture
Explanation:
because the energy substances must absorb in order to change from liquid to gas