Mechanics
This is defined as the distance moved in a stated direction.
What is displacement?
This is an example of a longitudinal wave.
What is a sound wave
This type of lense is responsible for converging rays to meet at F.
What is a convex lens.
A transformer operates on the principle of....
Mutual induction
This scientist was responsible for finding the element Radon.
Who is Marie Currie?
Velocity is defined as
The rate of change of displacement
State the wave equation..
The speed of a wave = wavelength x frequency
This is the lens formula..
1/u + 1/v = 1/f
What is a transformer ?
A devices that changes an alternating voltage to a larger or smaller one
Which scients were responsible for carrying out the alpha
Particle scattering experiment?
Who are Gieger and Marsden
State newton's 3rd law and give an example of it
If body A exerts a force of body B, body B exerts an equal but opposite force
On body A . Eg a person stepping off a boat to Pier, he moves fwd but boat moves back
The amplitude of a wave is described as...
The maximum height of a crest ( or trough) measured from the undisturbed position
Define the term total internal reflection
This occurs when a ray from a more optically dense medium , has an incident
Angle greater than the critical angle of the medium. No refracted ray is seen only
A reflection inside the medium
What is lenz law?
The induced current flows in a direction to oppose the change that causes it
In electromagnetism
The half life of a radio active element is ....
The time taken for 1/2 the sample to decay.
A ball of mass 1kg accelerates from rest down a ramp in 5 seconds and hit a block
If the finalV elocity was 25 m/s. What is the acceleration of the ball
and the force it struck the block .
Using acceleration, a= v-u / t
a = 25-0/5 = 5 ms-2
Force = mass x accel = 1kg x 5 = 5 N
List 4 properties of transverse waves
They all
1. Exhibit Reflection, refraction, diffraction, interference
2. Obey the wave equation
3. Are transverse waves
4. Travel at the speed of light in a vacuum
5. Consist of electric and magnetic fields perpendicular to each other and motion
6. They can travel in a vacuum
state the two laws of refraction
1. Incident ray, refracted ray and normal all lie in the same plane
2. The ratio sin θ1/sin θ2 =n, is the refractive index of a medium
A transformer has 200 coils in the primary and twice as many in the secondary.
If the voltage in the secondary is 20V .
Determine the voltage in the primary and power of primary part of the transformer
If the current Is 400 mA.
Vs/Vp = Ns /Np
400/200 = 20/Vp , Vp = 10 V
Power = I x V = 0.4 A x 10 A= 4W
It takes a radioactive sample to reach 1/16 of it's original value in 20 days
What is it's half life?
1st half life = 1/2 sample , 2nd = 1/4 sample, 3rd = 1/8 sample , 4th = 1/16 sample
20 days = 1/16 = 4 half lives
1 half life = 5 days
A ball of mass 50g is dropped from a 10 m tall building. ( Use g = 10N/kg)
Find the velocity just before impact
Use 1/2 mv2= mgh
v2 = 200
Velocity = 14.1 m/s
A sound wave has two crests appearing in 1 minute.
Determine its period and frequency
2 crests = 1 wavelength = 60 sec for the period
Frequency , f = 1/T = 1/60 = 0.016Hz
A ray travelling from air to an unknown medium has an incident angle of 30°
The refracted ray is 20 °. Determine the refractive index and critical angle
Refractive index n = sin 30/ sin 20 = 1.46
n = 1/ sin C
Sin C = 1/ 1.46, c = 43° (approximately)
State the motor rule
This is Flemming's LHR : hold the left hand with the first finger ,2nd finger and thumb
Perpendicular to each other . The first finger points direction of magnetic field, the 2nd
Finger points the direction of current, the thumb points the thrust on the wire (force)
A) Name TWO proposed models of the atom . The scientists responsible
B) Give a brief description of the model of the atom.
A) Plum pudding by JJ Thomson : positively charged sphere with electrons
Distributed like currants in a bun.
B) Nuclear model by Rutherford : small dense positive core, with majority of mass
Of the atom surrounded by electrons some distance away.