Physics - Doubts in the syllabus

[lavanyamane]

Need some help guys:

1. Recall and use the relation between force, mass and acceleration (including direction) - What does direction mean, here?
2. Page 15: Give advantages and disadvantages of each method in terms of cost, reliability, scale and environmental impact (talking about energy sources).
3. What exactly is nuclear fusion, in the Sun?
4. How is Brownian motion evidence for the kinetic molecular model of matter? What is this model anyway?
5. Give a molecular interpretation of latent heat.
6. How exactly would one define wavefront?
7. Use the simple electron model to distinguish between conductors and insulators.
8. Page 27: Describe an experiment to show the corresponding force on beams of charged particles (current-carrying conductor)
9. Describe the detection of alpha particles, beta particles and gamma rays.
10. Describe the deflection of radioactive emissions in magnetic fields.

 

[Adahshan]

Resultant force? Direction of resultant force.

Yes, Give advantages and disadvantages in energy resources. Simple

Nucleur fusion is how energy from the sun hits earth.

Brownian motion is movement of smoke particles in a zig zag motion due to particles in air bumping with the smoke particles. Smoke particles are big enough to be seen but have low mass.

Latent heat is the energy absorbed to change a state E=MxL

Wavefront - A wave passing after another wave.

Experiment for conductors and insulators, One which has wax and metal balls and the one which has the most balls fallen is teh best conductor.

Alpha and beta and gamma particles can be detected by cloud chamber or by GM tube.

Gamma rays are never defected by electrical or magnetic field but alpha does in direction to negative and beta in direction to positive.

THNX BUTTON IF HELPED ;D

 

[lavanyamane]

Resultant force? Direction of resultant force.

Yes, Give advantages and disadvantages in energy resources. Simple

Nucleur fusion is how energy from the sun hits earth.

Brownian motion is movement of smoke particles in a zig zag motion due to particles in air bumping with the smoke particles. Smoke particles are big enough to be seen but have low mass.

Latent heat is the energy absorbed to change a state E=MxL

Wavefront - A wave passing after another wave.

Experiment for conductors and insulators, One which has wax and metal balls and the one which has the most balls fallen is teh best conductor.

Alpha and beta and gamma particles can be detected by cloud chamber or by GM tube.

Gamma rays are never defected by electrical or magnetic field but alpha does in direction to negative and beta in direction to positive.

THNX BUTTON IF HELPED ;D

What you explained is not nuclear fusion.
I know what Brownian motion is, but what is the kinetic molecular model of matter?
I also know what latent heat is, but what is its molecular interpretation? Does it mean the same thing?
How is the electron model used to distinguish between conductors and insulators?
Could you elaborate on the functioning of a GM tube for radioactive detection?
I know their deflection in electric fields, but what about in magnetic fields?

 

[unplugged]

1. The direction of force indicates how it effects an object that has another force acting on it. 2 forces that are perpendicular to each other have no effect on each other , 2 forces in opposite directions negate each other and anything in between is a matter of resolving forces.
An important thing to remember is that Acceleration and velocity are both vectors , so they have a direction and speed is a scalar which means it has no direction.
That's really the extent of what you're going to be asked about , to understand that acceleration is a force with a direction and that effects an object that's already in motion in the way that the resultant force will be a mix of the 2 forces depending on their direction.

2. I think you can answer this on your own. You just need to learn the effect that fossil fuels have on the environment and how rare they are.

3. Nuclear fusion is when Helium atoms under immense pressure and heat (in the sun) come together to form hydrogen atoms(fusion) and this process produces a lot of energy which we
see in the form of light and heat(sun rays).

4. I'm not sure what you're asking , but the molecular model is the constitution of atoms
as we understand it. That is they have a nucleus containing protons and neutrons and they
have electrons that orbit in shells around it.

5. A molecular way of thinking of latent heat is that atoms have bonds between them and heat
makes those bonds weaker causing a change of state at certain points when those bonds break
and the atoms are more free to move around.

6. Here's a lovely definition of a wave front. It is the continuous line or surface including all the points in space reached by a wave or vibration at the same instant as it travels through a medium.

7. A conductor is any type of matter that has free electrons that can move around. Any
form of matter that has atoms with enough electrons to precisely satisfy it's neighboring
atoms is an insulator as the electrons are hard to move , although with enough energy
anything can be a conductor. Such as air.
8. Not sure what you're asking.

9. Geiger Counter, with Geiger-Mueller (GM) Tube or Probe—A GM tube is a gas-filled device that, when a high voltage is applied, creates an electrical pulse when radiation interacts with the wall or gas in the tube. These pulses are converted to a reading on the instrument meter.
The gas in the tube usually differs when detecting different radiations.

10. Alpha particles are 2 neutrons and 2 protons (a helium nucleus) and the charge on it is positive , so obviously they will be attracted to the south pole. And beta particles containing negative charge will be attracted to the north pole. Gamma rays have no charge and are not effected by magnetic fields.

 

[lavanyamane]

Thank you very much, unplugged. That was helpful
Are you sure that positive charges are attracted to the south pole and negative ones to the north pole?

 

[lavanyamane]

http://www.xtremepapers.me/CIE/Cambridg ... 7_qp_3.pdf
Q.3 (b)(ii) ?

 

[ajmanutd]

http://www.xtremepapers.me/CIE/Cambridge%20IGCSE/0625%20-%20Physics/0625_w07_qp_3.pdf
Q.3 (b)(ii) ?

moment of force=distance from d pivot X weight of d load

hope it helped

 

[lavanyamane]

That's what the mark scheme says.. But why? The force is concerned with the spring, right? So why does the load come into picture?

 

[burndtjamb]

Thank you very much, unplugged. That was helpful
Are you sure that positive charges are attracted to the south pole and negative ones to the north pole?

The information he gave you concerning that point is wrong, north and south poles are not the same as positive and negative charges.

To determine where radiation is deflected in a magnetic field, Fleming's left hand rule is used. It's explained here: http://www.furryelephant.com/content/ra ... lpha-beta/

 

[AnnoyingCarrot123]

Can someone help me with "Describe simple experiments to show the production and detection of electrostatic charges".

 

[rockincrew]

using gold leaf electroscope
the attachment show its picture

 

[medevil]

http://www.xtremepapers.me/CIE/Cambridg ... 2_qp_3.pdf
Question 2b and 2c i know whats there in the marking scheme but its not explained properly if anyone could help me out

 

[ajmanutd]

That's what the mark scheme says.. But why? The force is concerned with the spring, right? So why does the load come into picture?

this is d formula fr moment of force and d question is asking hw moment of force is calculated so that is why we hav 2 give this formula..
the spring is juz der 2 to equalize d moments of d load..

 

[lavanyamane]

Ok but then why the forcw exerted by the load and the distance till the spring??

 

[AnnoyingCarrot123]

Can someone explain why Capacitors are used in time-delay circuits?

 

[ajmanutd]

Ok but then why the forcw exerted by the load and the distance till the spring??

d distance is nt till the spring it is the distance from the spring to the pivot..

 

[lavanyamane]

Ya I know, but why? distance from the pivot to the spring but then why the weight of the load?

 

[ajmanutd]

Can someone explain why Capacitors are used in time-delay circuits?

capacitors store charge.
since they take time to store the maximum amount of charge they cn store.. the circuit gts its optimum amount of current only wen the capacitor is full..
so this why a capacitor is used in a time-delay circuit..

hope u gt it..

 

[ajmanutd]

Ya I know, but why? distance from the pivot to the spring but then why the weight of the load?

bcz a diagram fr moment of force has to have 2 weights 2 compare..
bt d question asks fr a formula fr moment of force so u write d formula only..

 

[igcse2011]

Need Help with :
1-use the term half-life in simple calculations, which might involve information in tables or decay curves.
2-use and describe use of a cathode-ray oscilloscope to display waveforms.
3-Explain why energy losses in cables are lower when the voltage is high ?
4-Describe an experiment to measure specific latent heats for steam and for ice and experiment for specific heat capacity