Chapter 9 - 12

Question 1

Kirchhoff’s First Law

Answer 1

Sum of currents entering any junction are always equal to the sum of currents leaving.

Question 2

Kirchhoff’s Second Law

Answer 2

Sum of the EMF in a circuit is equal to the p.d of the components.

Question 3

Series circuit rules

Answer 3

Components connected in one loop.
Current same around whole circuit.
Total p.d is sum of components p.d

Question 4

Parallel Circuit rules

Answer 4

Components connected in different loops
Current is added up at the top of circuit
P.d is same around circuit

Question 5

Electromotive Force

Answer 5

When charges gain energy from power supply.

Work done on charge carriers

Question 6

Potential Difference

Answer 6

Measure of electrical energy

Measures energy loss.

Question 7

Ohms Law

Answer 7

For a metallic conductor kept at constant temperature, the current is directly proportional to the p.d across the ends.

Question 8

When temperature of wire increases

Answer 8

Positive ions gains internal energy and vibrate more
Frequency of collisions increase, resistance increases
More energy transferred when travelling through wire,

Question 9

3 factors affecting resistance

Answer 9

Material of wire
Length of Wire
Cross sectional area

Question 10

Thermistor

Answer 10

Electrical component made from semi conductor with negative temperature co - efficient. As temperature increases, resistance decreases

Question 11

Resistivity Equation

Answer 11

R = pL / A

Question 12

Internal Resistance

Answer 12

When there is a current in the power source, energy is lost which is transferred to heat.
EMF = terminal p.d + lost volts`

Question 13

Potential Divider Equation

Answer 13

V out = (R2/ R1 + R2) x V in

Question 14

Longitudinal Wave

Answer 14

Direction of movement is parallel to transfer of energy direction.

Question 15

Transverse Waves

Answer 15

Direction of movement is perpendicular to transfer of energy direction.

Question 16

Give examples of transvers waves

Answer 16

EM waves
Seismic Waves
Waves of surface of water

Question 17

Example of longitudinal wave

Answer 17

Sound Waves

P - Waves

Question 18

Define Progressive Waves

Answer 18

An oscillation that travels through matter

They all transfer energy

Question 19

Wave speed equation

Answer 19

frequency x wavelength

Question 20

frequency equation

Answer 20

1 / time

Question 21

Phase Difference

Answer 21

The difference between displacements of particles along a wave.

Question 22

Reflection

Answer 22

When a wave changes direction at a boundary.

Question 23

Refraction

Answer 23

When a wave changes direction as it changes speed, passing from one medium to another.

Question 24

When wave slows down wavelength…..

Answer 24

decreases

Question 25

Diffraction

Answer 25

When waves pass through a gap or obstacle the waves will spread out. Speed, wavelength, frequency remains same.

Question 26

Polarisation

Answer 26

When the particles oscillate in only one direction. | Confined to a single plane.

Question 27

Partial Polarisation

Answer 27

When transverse waves reflect off a surface, they become partially polarised.

Question 28

Which type of wave is already polarised

Answer 28

Longitudinal Wave

Question 29

Intensity

Answer 29

The power passing through a surface per unit area. I = P/A

Question 30

What is intensity proportional to?

Answer 30

( Amplitude )^2

Question 31

what is c equal to

Answer 31

3 x 10 ^ 8

Question 32

Refractive Index equations ( 3 )

Answer 32

n = c / v n = 1/sin c n1 sin theta 1 = n2 sin theta2

Question 33

Total Internal Reflection

Answer 33

When a light ray strikes a boundary at a larger angle to the normal, it will be totally internally reflected.

Question 34

What are the two conditions for TIR

Answer 34

The light must be travelling through a medium with a higher refractive index as it hits the boundary The angle at which it hits must be higher than the critical angle.

Question 35

Principle of superposition of waves

Answer 35

When two or more waves cross at a point, the displacement at that point is equal to the sum of displacements of the individual waves.

Question 36

Constructive interference

Answer 36

For two waves in phase, the maximum positive displacements add together.

Question 37

Destructive Interference

Answer 37

For two waves in antiphase, the maximum and minimum of each wave form a smaller waves

Question 38

Coherence

Answer 38

When waves emitted from two sources have a constant phase difference. Must have same frequency

Question 39

Path Difference

Answer 39

The distance a wave has travelled from its source to any point the wave. Distance - m

Question 40

Phase Difference

Answer 40

The difference between two waves when they pass the same point. Degrees / Radians

Question 41

Youngs double slit formula

Answer 41

``` lambda = ax / D D = distance from slit to screen x = width of light ray a = gap between the slits ```

Question 42

Stationary Waves

Answer 42

Formed when two waves with the same frequency and amplitude traveling towards each other are superposed

Question 43

Node

Answer 43

The two waves cross at the middle when displacement is equal to 0

Question 44

Antinode

Answer 44

The waves meet at maximum displacement.

Question 45

Energy transfer in progressive waves vs stationary waves

Answer 45

Progressive - Energy transferred in the direction of the waves Stationary - No net energy transfer

Question 46

Wavelength in progressive waves vs stationary waves

Answer 46

Progressive - Minimum distance between two adjacent points in phase Stationary - Twice the distance of two adjacent nodes.