Question

1) Calculate the work done in moving a charge of 5 coulomb from a point at 220 volt to another point at 230 volt.
2) What is electric current ? Name Sl unit of current.
3) State the relation between milliamperes and ampere and microampere and ampere.
4) State how an ammeter and a voltmeter are connected in a circuit.​

Answer 1

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• 1. We know that potential difference = Work done/Charge moved.

In this case, V = 230 V and V2 = 240 V.

The mount off charge moved = 5 C.

Thus, the potential difference = v2-V1 = 230-240 = 10 V

Therefore, Work done = Potential difference * Charge moved.

That is, 10 * 5 = 50 Joules.

Hence, the work done in moving a charge of 5 coulombs from a point at 230 volts to another point at 240 volts is 50 J.

• 2 . Ampere The SI unit of electric current is the ampere, or amp, which is the flow of electric charge across a surface at the rate of one coulomb per second.

• 3. 1 ampere is equal to 1000 milliamperes, or 1000000 microamperes.

• 4. The voltmeter is connected in parallel with the circuit to be measured. We do not want the voltmeter to load the circuit. Consequently an ideal voltmeter will have infinite resistance. An ammeter is connected in series with the circuit to be measured.

Answer 2

Required solution :-

Solution I :-

Given :-

Charge moved = 5 C

v₁ = 220 V

v₂ = 230 V

To Find :-

The work done in moving the charge.

Solution :-

We know that,

• w = Work
• p = Potential difference
• c = Charge moved

According to the question,

Potential difference = v₂ - v₁

= 230 - 220

= 10 V

By the formula,

$\underline{\boxed{\sf Work \ done=Potential \ difference \times Charge \ moved}}$

Given that,

Potential difference = 10 V

Charge moved = 5 C

Substituting their values,

w = 10 × 5

w = 50 J

Therefore, the work done is 50 J.

Solution II :-

Electric current is defined as the rate of flow of electrons in a conductor.

Electrons having negative charge, protons having positive charge.

There are two types of electric current:

• Direct current (DC)
• Alternating current (AC)

The magnitude of electric current is measured in coulombs per second. The SI unit of electric current is ampere and is denoted by the letter A.

Solution III :-

One milliampere is equal to 1000 amperes. One Ampere is equal to 1000000 or 10⁻⁶ microamperes.

The unit of electric current that is equal to the flow of one coulomb per second. (Ampere = 1 Coloumb/ second)

Solution IV :-

The ammeter is used from measuring small amount of current while voltmeter is used to measure the potential.

An ammeter is connected in series with the circuit and its accuracy is more while voltmeter is connected in parallel with the circuit and its accuracy is less.

Both the devices has same connection polarity. The negative potential is joined with the negative polarity and positive terminal is joined with the positive polarity of the supply.