Explanation

A voltmeter is used to measure the potential difference (voltage) across two points in a circuit.

It is connected in parallel with the component whose voltage is being measured.

Explanation

The ampere, symbol A, is the SI unit of electric current.

It is defined by considering the fixed  value of the elementary charge e as 1.602 176 634 x 1019,

where the unit C is equal to As and the second is defined by Δν Cs.

Explanation

Red light rays have the lowest frequency and highest wavelength value.

Blue or violet light has the shortest wavelength.

Explanation

The hertz is the unit of frequency of one cycle per second. 

 symbol: hertz (Hz)

Hertz in honor of the German physicist Heinrich Hertz

hertz in the International System of Units (SI)

frequency is defined as one cycle per second

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Explanation

The coulomb, also written as its abbreviation 'C', is the SI unit for electric charge.

One coulomb is equal to the amount of charge from a current of one ampere flowing for one second.

One coulomb is equal to the charge on 6.241 x 1018 protons.

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