P2: Electricity (triple)

Question 1

What is current?

Answer 1

Current is the flow of electrical charge.

Question 2

What is an ohmic conductor?

Answer 2

A component with a constant resistance at a constant temperature.

Question 3

What is an LDR?

Answer 3

A light dependent resistor increases resistance as the intensity of light decreases.

Question 4

What is a thermistor?

Answer 4

A type of resistor that increases resistance when the temperature decreases.

Question 5

What are the rules of a series circuit?

Answer 5

Potential difference is shared
Current is the same everywhere
Resistance adds up

Question 6

What are the rules of a parallel circuit?

Answer 6

Potential difference is the same across all components
Current is shared between branches
Adding a resistor in parallel reduces the total resistance

Question 7

How is potential difference changed from a power station to A consumer?

Answer 7

1. The voltage is increased at a step-up transformer.
2. The electricity travels along large pylons.
3. The voltage is decreased at a step down transformer.
4. The electricity is now ready for domestic use.

Question 8

What are sensing circuits used for?

Answer 8

increasing the power to or turning on components in a circuit depending on the conditions they are in.

Question 9

How is static built up by friction?

Answer 9

when certain insulating materials are rubbed together, electron are scraped off from one to the other. This leaves one with a negative static charge and the other with a positive static charge.

Question 10

How can too much static cause sparks?

Answer 10

the static charge on an object increases to the extent that the potential difference is large enough for electrons to jump across form the object to earth.

Question 11

Which way do electric field lines go?

Answer 11

from positive to negative.