Given that metal cases of electrical appliances are connected to the wire, let's select the statement which is not correct from the list of statements.
The earth wire is used to protect you and help reduce the risk of receiving an electric shock. The earth wire reduces the risk of electric shock by creating a path for a fault or lose current to flow to the Earth.
The Live wire may become loose and touch the metal case. In this case, the earth wire will channel the fault current to the earth thereby reducing the risk of electric shock.
If the metal case becomes live, the earth wire conducts current to the ground. This helps prevent electric shock from the metal case.
The Earth wire has low or no resistance. It is always made of copper.
It provides a low resistance path to the ground.
Therefore, the statement ''the earth wire needs to have high resistance'' is NOT current.
ANSWER:
C. The earth wire needs to have a high reistance.
The formula is F = ( q1 * q2 ) / r ^ 2
<span>where: q is the individual charges of each ion </span>
<span>r is the distance between the nuclei </span>
<span>The formula is not important but to explain the relationship between the atoms in the compounds and their lattice energy. </span>
<span>From the formula we can first conclude that compounds of ions with greater charges will have a greater lattice energy. This is a direct relationship. </span>
<span>For example, the compounds BaO and SrO, whose ions' charges are ( + 2 ) and ( - 2 ) respectively for each, will have greater lattice energies that the compounds NaF and KCl, whose ions' charges are ( + 1 ) and ( - 1 ) respectively for each. </span>
<span>So Far: ( BaO and SrO ) > ( NaF and KCl ) </span>
<span>The second part required you find the relative distance between the atoms of the compounds. Really, the lattice energy is stronger with smaller atoms, an indirect relationship. </span>
<span>For example, in NaF the ions are smaller than the ions in KCl so it has a greater lattice energy. Because Sr is smaller than Ba, SrO has a greater lattice energy than BaO. </span>
<span>Therefore: </span>
<span>Answer: SrO > BaO > NaF > KCl </span>
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Answer:
Gamma rays are mostly used in the radiotherapy/ radiooncology to treat cancer. They can also be used to spot tumours. Gamma rays can kill living cells and damage malignant tumor
