4.3 Electrical Circuits Flashcards Preview

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Flashcards in 4.3 Electrical Circuits Deck (12)
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1

What is Kirchhoff's first law?

The sum of currents entering a junction (or node) in a circuit is equal to the sum of the currents leaving the junction

2

What is Kirchhoff's second law?

In any closed loop, the sum of the emf is equal to the sum of the products of the current and resistance.

3

What is the potential divider equation?

Vout= Vin x R2/(R1+R2)

4

What are the variations on a potential divider circuit?

Variable resistor
Thermistor
LDR

5

What is a potential divider circuit?

It uses two resistors in series to split or divide the voltage of the supply in a chosen ratio so that a chosen voltage can be provided to another device or circuit.

6

What is terminal pd?

The potential difference recorded across the terminals of a cell.

7

What are lost volts?

The difference between the emf and the terminal pd when charge flows

8

what is internal resistance?

The resistance to electric current of the materials inside a source. When current flows, energy is transferred to these materials, resulting a drop in the terminal pd.

9

Equation for emf with r

e = I(R+r)

10

Define kilowatt hour

Energy transformed by a device working at 1kW for 1h

11

Explain why Resistivity rather than resistance of a material is given in tables of properties of materials.

p is independent of dimensions of the specimen of the material.

12

Why is it not advisable to maintain high currents for a long time?

Excessive heating of CELL/ energy wasted INTERNALLY