Nabteb 2109 Basic Electricity OBJ:

1-10=BCAABCABBC

11-20=CCDAACABBA

21-30=BADDDCCDAB

31-40=CBDCCDACBA

(1ai)

Frequency is the number of periods or regularly occurring events of any given kind in unit of time, usually in one second.

(1aii)

Power factor is the ratio of the actual electrical power dissipated by an AC circuit to the product of the r.m.s. values of current and voltage.

(1aiii)

Impedence(z) is the overall opposition of a mixed circuit containing a resistor,an inductor and/or a capacitor. It is measured in ohms

(2a)

Kirchhoff's current law (1st Law) states that current flowing into a node (or a junction) must be equal to current flowing out of it. This is a consequence of charge conservation.

Kirchhoff's voltage law (2nd Law) states that the sum of all voltages around any closed loop in a circuit must equal zero.

(4ai)

(Pick two)

(i)Current (amperage) will be constant throughout the circuit.

(ii)Total resistance of the circuit is equal to the sum of each individual resistance.

(iii)Total voltage of the circuit is equal to the sum of the individual voltage drops across each component.

(4aii)

(Pick two)

(i)parallel circuit has two or more paths for current to flow through.

(ii)Voltage is the same across each component of the parallel circuit.

(iii)The sum of the currents through each path is equal to the total current that flows from the source.

(4b)

CLICK HERE FOR THE IMAGE

(4c)

In parallel

if you removed 15 Î©

Resistance will remain unchanged, so the current through it is unchanged

In series

if you removed 15 Î©

It goes out

Removing one resistor result in an open circuit. No current flow

(6a)

Self-inductance or in other words inductance of the coil is defined as the property of the coil due to which it opposes the change of current flowing through it. Inductance is attained by a coil due to the self-induced emf produced in the coil itself by changing the current flowing through it.

(6aii)

Mutual Inductance is defined as the property of the coil due to which it opposes the change of current in the other coil, or you can say in the neighboring coil. When the current in the neighboring coil is changing, the flux sets up in the coil and because of this changing flux emf is induced in the coil called Mutually Induced emf and the phenomenon is known as Mutual Inductance.

(6aiii)

Magnetomotive force also known as magnetic potential, is the property of certain substances or phenomena that gives rise to magnetic field . Magnetomotive force is analogous to electromotive force or voltage in electricity.

The standard unit of magnetomotive force is the ampere-turn (AT)

7a)

i)Series circuit

II)Parallel circuit

III)Combination circuit

(7b)

Soldering is a process in which two or more metal items are joined together by melting and flowing a filler metal into the joint, the filler metal having a lower melting point than the workpiece.

(7c)

(i)To prevent oxidation of the base and filler materials.

(ii)flux is used as threefold purpose, as it removes the oxidized metal from the surface to be soldered.

(7d)

(i)Lead-based solder

(ii)Lead-free solder

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