Physics Grade 9

Question 1

What is electrochemical cells

Answer 1

Is a package of chemicals that converts chemical energy into electric energy which is stored in charged particles

Question 2

What is potential difference/ voltage

Answer 2

Potential energy is energy that is stored in a object ie, a battery measured in Volts

Question 3

What is current

Answer 3

Current is a measure of the amount of electric charge that passes by a point in a circuit each second measured in Amps

Question 4

What is resistance

Answer 4

Resistance is the degree to which a substance opposes the flow of electric current through it measured in Ohms

Question 5

ohms law formula

Answer 5

V= IxR
R=V/I
I=V/R

Question 6

what is ohms law

Answer 6

ohms law is the relationship between potential difference (V) current (I) resistance (R)

Question 7

1000milliamps in amps

Answer 7

1 Amp

Question 8

What is energy

Answer 8

Energy is the ability to do work
Symbol: E
Measured in: Joule J

Question 9

What is power

Answer 9

Power describes how quickly or slowly an electrical load uses energy
Symbol: P
Measured in: Watts W

Question 10

What is percent efficiency and formula

Answer 10

Percent efficiency tells us how much of the original energy is actually converted into the desired output energy
Measured in: %efficiency= OE/IE x100

Question 11

Cost units

Answer 11

Power:kW
Time: H
Rate: $/kWh
Cost= PxTxRate

Question 12

Energy formula

Answer 12

E=VxIxt
Energy: J
Voltage: V
Current:A
Time: s

Question 13

Power formula

Answer 13

P=E/t
P=VxI
Power:W
Energy: J
Time: s

Question 14

Voltage Series and Parallel

Answer 14

Series: Vt= v1+v2+v3
Parallel: Vt= v1=v2=v3

Question 15

Current Series and Parallel

Answer 15

Series: It=I1=I2=I3
Parallel: It=I1+I2+I3

Question 16

Resistance Series and Parallel

Answer 16

Series: Rt=R1+R2+R3
Parallel: Rt= 1/R1+ 1/R2+ 1/R3