Topic 10

Question 1

potential

Answer 1

how much electrical energy each of the electrons have
difference in every used or work done by each electron as it travels around the circuit
measured in volts using a voltmeter

Question 2

current

Answer 2

when electrons are all moving/ flowing in one direction
rate of flow of charge

Question 3

what affects teh size of a current

Answer 3

increasing surface area
speed
how many electrons there are

Question 4

electrons flow

Answer 4

anticlockwise (- to +)
opposite to convectional current :
+ to -

Question 5

why do we use circuit symbols

Answer 5

universal
easier to understand

Question 6

series

Answer 6

compleet loop

Question 7

parallel

Answer 7

multiple loops connected together

Question 8

voltmeter

Answer 8

is always attached to teh bulb in parallel
still a series cuircut

Question 9

ameter

Answer 9

attched in series to the bulb

Question 10

current in series

Answer 10

the current is the same at any point because all the ekectrons are all moving at the same speed

Question 11

current in parallel

Answer 11

the current splits approx in hald between the loops

Question 12

potential difference between bulbs in series cuircuit

Answer 12

adds up to potential difference of the cell

Question 13

earth wire

Answer 13

• yellow and green
• attached to the metal parts/ casings of the component in case the live wire detaches and touches the metal part
• attached to metal spike in the ground
• 0V

Question 14

neutral wire

Answer 14

• blue wire
• provides a return route for current to flow back to the powerstation
• 0V

Question 15

live wire

Answer 15

• brown wire
• current flows through this wire to the required parts of the appliance
• maintains 230V

Question 16

fuse

Answer 16

to protect the lead rather than the appliance. It is a deliberate weak link in a circuit, which will blow if an electrical appliance or extension lead draws too much current due to either an overload or a fault.

Question 17

electrical items get hotter due to resistance

Answer 17

• when the electrons flow through the wire there are collisions that cause vibrations between electrons and cations in the metal
• collisions cause vibrations in the ions and the electrical energy is transferred to thermal energy and dissipated into the surroundings
• heating will further increase the resistance of the circuit

Question 18

why does heating cause more resistance

Answer 18

• more heating leads to more ions vibrating
• because more KE
• meaning more ions will collide with more electrons
• therefore its harder for electrons to flow and current has decreased

Question 19

which components provides the push for electrical current

Answer 19

battery

Question 20

whats the push of teh electrons supplied by the battery

Answer 20

p.d.

Question 21

diode

Answer 21

component that has more resistance in one direction than the other
- therefore only allows current in one direction
- used to protect simple cuirits from damage like remote conteolers

Question 22

if there are more electrons

Answer 22

current increases so resistance decreases

Question 23

LDRs

Answer 23

• resistance is not fixed
• dependant on light intensity
• high resistace in teh drak

Question 24

resistnace

Answer 24

• electrons can’t get infinitely faster in a wire due to limited surface pressure
• mesured in ohms

Question 25

change

Answer 25

C Clomb

Question 26

The student used a power supply that had fixed output voltage settings. Each of these outputs was a whole number of volts. Describe how the student could add a component to the circuit that would provide a continuously variable voltage across the lamp.

Answer 26

variable resistor, parallel to bulb with power pack

Question 27

State the measurements that the student must take to find the overall resistance of the resistors in parallel

Answer 27

potential difference drops across resistors in parallel so ammeter reads the current n the cuircit

Question 28

There is a current of 2.3 A in the radio when the radio is working correctly. Which of these should the technician choose to protect the radio circuit?

Answer 28

5A