4.1 charge and current

Question 1

charge unit

Answer 1

C

Question 2

elementary charge

Answer 2

1.6 x 10-19

Question 3

current

Answer 3

rate of flow of charge
Q = I
T

Question 4

current unit

Answer 4

A

Question 5

how to measure current in circuit

Answer 5

ammeter in series

Question 6

conventional current

Answer 6

current flowing from positive to negative terminal

Question 7

electron flow

Answer 7

negative to positive

Question 8

mean drift velocity definition

Answer 8

average flow of charge along the wire

Question 9

mean drift velocity equation

Answer 9

A = cross sectional area (m2)
n = number of charge carriers per unit volume (m-3)
e = charge of 1 carrier (C)
I = current (A)

Question 10

value of n in conductor

Answer 10

high value

Question 11

value of n in insulator

Answer 11

low value

Question 12

law of conservation of charge

Answer 12

current cannot be created or destroyed

Question 13

kirchoff’s first law

Answer 13

total current leaving a junction is equal to the total current entering a junction

Question 14

state the charge carriers in a metal

Answer 14

free electrons

Question 15

state the charge carriers in an electrolyte

Answer 15

ions

Question 16

describe the motion of electrons in a wire that doesn’t have p.d across it

Answer 16

random motion at high speeds

Question 17

what causes a semi-conductor to conduct a higher current

Answer 17

an increase in its temperature which leads to an increase in its n