electrical quantities

Question 1

how to charge a negative rod by friction

Answer 1

rub a rod with cloth- negative electrons will move from the cloth to the rod- cloth becomes positive and

Question 2

non metals can be charged by what

Answer 2

friction

Question 3

to protons or electrons move

Answer 3

electrons

Question 4

neutral objects are attracted or repuled to charged objects

Answer 4

atrracted

Question 5

positive point field lines

Answer 5

away from point

Question 6

negative point field lines

Answer 6

towards point

Question 7

uniform electric field field lines

Answer 7

towards negatuve plate

Question 8

how to charge by induction

Answer 8

1) uncharged metal sphere on a insulator
2) charged rod close to sphere
3) earth the metal- neelectrons neutralize + charges
4) remove earth connection

Question 9

what is electric current

Answer 9

the rate of flow of charge

Question 10

formula of current

Answer 10

current= charge/time

Question 11

why are metals good conducters of electricity

Answer 11

because theyr have free electrons which are free to move and carry a charge

Question 12

what is a non metal that conducts

Answer 12

graphite carbon

Question 13

what are examples of insulators

Answer 13

water

Question 14

how does temperature effect current

Answer 14

the bigger the temperature the flow of current decreases and resistance increases becuse electrons are harder to move with more metal ions collding

Question 15

what is potential difference or “voltage”

Answer 15

p.d pushes electrons and gives them energy to move around a circuit
work done by a unit of charge passing by a component
p.d= work/charge

Question 16

the cells in series adds uo to the total

Answer 16

p.d (e.m.f)

Question 17

what is resistance

Answer 17

the opposition to the flow of current
resistance=p.d/current

Question 18

what is conventional current

Answer 18

the flow of electrons

Question 19

what is electromotive force

Answer 19

the electrical work done by a souce in moving unit charge around a complete cirasuit

Question 20

emf formula

Answer 20

e=w work/ charge

Question 21

what do electrical circuit do

Answer 21

they transfer energy from a source of electrical energy like cells or a main supply to the circuit components eg: lamps and then to the surroundings as heat

Question 22

electrical power supplied by cells= …..

Answer 22

total power udes by circuit components

Question 23

what is power

Answer 23

power is the rate of doing work (changing energy)
power= energy change/ time
or
power = voltage x current
power= v2/R

Question 24

what is ohms law

Answer 24

current is porportional to potential difference at constant temperature

Question 25

what is the difference between ac and dc

Answer 25

In DC, the electrons flow steadily in a single direction, while electrons keep switching directions, going forward and then backwards in AC.

Question 26

flow of electrons and direction of current

Answer 26

State that conventional current is from positive
to negative and that the flow of free electrons is
from negative to positive

Question 27

resistance formula

Answer 27

resistance= V/I

Question 28

relaishonship between length of wire and resistance

Answer 28

the bigger the length the bigger the resistance
porportional
R1/L1= R2/L2

Question 29

relaishonship between cross section of a waire amd resstance

Answer 29

resistance is inversely porportional to cross section
R1xA1=R2xA2

Question 30

relaishonship between free electrons and resstance

Answer 30

the more free electrons the mor resistanve
R1xR1^2=R2xR2^2

Question 31

relaishonship between temperature and resistance

Answer 31

the bigger the temp the bigger the resistance
R1xd1^2/L1=R2xd2^2/L2