S2

Question 1

How do waves transfer energy

Answer 1

Waves transfer energy from one point to another using vibrations

Question 2

Types of progressive wave

Answer 2

Transverse, a wave which travels perpendicular to the direction of wave travel

Longitudinal, a wave which travels parallel to the direction of wave travel

Question 3

Examples of longitudinal waves

Answer 3

Sound waves and ultrasound waves

Question 4

Transverse waves

Answer 4

Water and electromagnetic

Question 5

Frequency

Answer 5

The complete number of oscillations generated per second, is represented by f and measured in hertz/Hz

Question 6

Wavelength

Answer 6

The distance between successive particles which are at the same point in their paths at the same time and are moving in the same direction

Question 7

Amplitude

Answer 7

The maximum displacement of particles in the wave train from their rest positions

Question 8

Ultrasound/ultrasonic sound + uses

Answer 8

Sound waves above 20,000 hertz, humans can’t hear them

Used in medicine to measure foetal head diameter and in industry to detect defects in metals

Question 9

Uses of sonar and radar

Answer 9

Sonar uses sound pulses to detect objects underwater

Radar uses electromagnetic pulses to detect aircrafts and ships

Question 10

Electromagnetic spectrum

Answer 10

Radio waves
Microwaves
Infrared radiation
Visible light
Ultraviolet radiation
X-rays
Gamma rays

Question 11

Results of overexposure from electromagnetic spectrum

Answer 11

Microwaves can cause internal heating of body tissues

Infrared radiation can cause skin burns

Certain ultraviolet wavelengths cause skin cancer

Large doses of radio waves can cause cancer, leukaemia and other disorders

X-Rays and gamma rays can cause cancer

Question 12

Refraction through a spectrum

Answer 12

The greater change of speed the greater the refraction. Red is refracted the least so it’s slowed the least, violet is refracted the most so it’s slowed the most

Question 13

Critical angle & total internal reflection

Answer 13

Below critical angle = reflected ray + weak refracted ray

At critical angle = reflected ray + refracted ray at 90 degrees

Beyond critical angle = strong reflected ray + no refracted ray

Question 14

Difference between long sight and short sight

Answer 14

Long sight: Hyperopia Long Sight Convergence corrected by Lens Convex Converging, lens too weak eyeball too short

Short sight: Short Sight Diverging Myopia corrected by Lens Concave Diverging, lens too strong eyeball too long

Question 15

Conductors vs insulators

Answer 15

Conductors have many free electrons while insulators have little to none

Question 16

Conventional current

Answer 16

The theory that electrons flow from a negative terminal to a positive, this has been proven false

Question 17

Charge equation

Answer 17

Charge (Coulombs) = Current x Time

Question 18

Voltage equation

Answer 18

Voltage (Volts/V) = Current (Amperes/A x Resistance (Ohms/I)

Question 19

Energy & power equations

Answer 19

Energy = Power x Time

Power = Current x Voltage

Question 20

Flemming’s left hand rule

Answer 20

Hold the thumb and first two fingers of the left hand at right angles to each other with the First finger pointing in the direction of the Field and the seCond finger in the direction of the Current then the Thumb points in the direction of the Thrust

Question 21

How is a star formed

Answer 21

1. Stars are formed when gravitational attraction pulls together amounts clouds of hydrogen gas and dust (called nebulae).
2. This matter is pulled together very high temperatures are created as the gravitational potential energy of the gas is converted to kinetic energy.
3. Temperatures as high as 15,000,000 K are reached and at such temperatures nuclear fusion occurs. The hydrogen nuclei fuse together to form Helium nuclei.
4. During nuclear fusion where light nuclei fuse together to form heavier nuclei a huge amount of energy is released. A star has started to form.
5. As the clouds of dust and gas initially collapse, they may cause the cloud to spin and as the cloud becomes more dense the spin rate increases.
6. As the core becomes hot it may separate from the spinning cloud, which then takes the shape of a flat spinning disc.
7. The hot core becomes the sun and the outer gases condense to form asteroids which then gather together to form the planets and other orbiting bodies.

Question 22

How might the centripetal force increase

Answer 22

The centripetal force will increase if;

The mass (m) of the object increases

The speed (v) of the object increases

The radius (r) of the orbit decreases

Question 23

Fleming’s right hand rule

Answer 23

Hold the thumb and first two fingers of the right hand at right angles to each other with the First finger pointing in the direction of the field and the thuMb in the direction of the Motion of the wire then the second finger points in the direction of the induced Current

Question 24

Equation for centripetal force

Answer 24

F = mv2/r