A scale and a ruler. The scale to measure the mass, and a ruler to measure the volume.
Answer:
group d
Explanation: because it goes back the most amount of years
Explanation:
The number acquired by an element after the lose or gain of an electron is called oxidation number.
For example, 
Here, oxidation number of Fe(s) is 0 and Fe in
is +3.
Oxidation number of O in
is 0 as it is present in its elemental state.
The oxidation number of O in
is calculated as follows.

Hence, oxidation number of O in
is -2.
- The loss of electrons by an element or substance is called oxidation. Here, electrons are being lost by Fe(s) as an increase in oxidation state is occurring. So, Fe(s) is oxidized.
- The gain of electrons by an element or substance is called reduction. Here, electrons are being added to
as a decrease in its oxidation state is occurring. So,
is reduced.
- An element or compound which is being reduced is called oxidizing agent. Here,
is the oxidizing agent.
- An element or compound which is being oxidized is called reducing agent. Here, Fe(s) is the reducing agent.
Answer:

Explanation:
Given that;
The energy gap between the valence band and the conduction band in the widely-used semiconductor gallium arsenide (GaAs) is Δ = 1.424 eV.
So; that implies that:

Suppose that we consider a small piece of GaAs with 1020 available electrons, -- This is taking about the numbers of electrons used which is :

Temperature is given as:

Number of electrons can be calculated by using the formula;


