Unit 4 Physics Edexcel A2 and Edexcel IAL

Do you by any chance know why we have to times E by cos49 ?

Posted from TSR Mobile

1466172528911.jpg34.9KB

Reply 142

Original post by pinksmartiee

Can someone help me with Q13? I don't even understand what this is asking.. Thanks!

https://60abffc9b401b1c0936e01291c15112cab0778c4.googledrive.com/host/0B1ZiqBksUHNYVFI1YlJBOWhwRW8/June%202014%20QP%20-%20Unit%204A%20AQA%20Physics.pdf

I think this is something to do with the inverse square law, we know that the force between two charged objects is inversely proportional to the square of distance between them. So, with the relationship that's given to us, i.e 20mm distance->0.5 N Force...We have to make some link. It's given that the point charges exert a force F and distance is given d. If you notice that F is actually the double of 0.5 F, so this means the distance must decrease by 4 times to produce double the force.

Reply 143

Original post by ayvaak

Do you by any chance know why we have to times E by cos49 ?

Posted from TSR Mobile

Yeah,I guess so because you need the resultant i.e overall electric field strength so that's the only way you will get it because at B,both charges are producing an effect.

(edited 7 years ago)

Reply 144

Original post by sabahshahed294

Yeah,I guess so because you need the resultant i.e overall electric field strength so that's the only way you will get it because at B,both charges are producing an effect.

so the result E would be the horizontal line between them?

Reply 145

Original post by ayvaak

so the result E would be the horizontal line between them?

Yes, I believe so. :s-smilie:

Reply 146

Does anyone know why the answer is B? I keep gettig answers that arent the options :smile:

Thanks in advance

1466178075199.jpg32.8KB

Reply 147

Original post by ayvaak

Does anyone know why the answer is B? I keep gettig answers that arent the options :smile:

Thanks in advance

Force= Charge multiplied by Electric Field Strength so Force= Mass into Acceleration meaning ma= qE so you know the mass of proton, charge and electric field strength. You can just rearrange the formula.

Reply 148

Mowerharvey

Is physics unit 4 anyone else's last exam?

Reply 149

Original post by sabahshahed294

Force= Charge multiplied by Electric Field Strength so Force= Mass into Acceleration meaning ma= qE so you know the mass of proton, charge and electric field strength. You can just rearrange the formula.

Posted from TSR Mobile

Thank you again.

Why cant you do these calculations in radians as apposed to degrees mode on the calc?

(edited 7 years ago)

1466180774635.jpg39.5KB

Reply 150

pinksmartiee

1

Original post by sabahshahed294

For 15(aiii), it's linked with the previous parts above. When it was in position Y, the capacitor was discharging. In position X, what's happening is that the capacitor begins to charge as it's now connected to the battery.
For 16(bii), you have to calculate the momentum first so as to apply the equation lambda=plank's constant divided by momentum. You have the energy and speed of light. Simply substitute them.

Original post by sabahshahed294

I think this is something to do with the inverse square law, we know that the force between two charged objects is inversely proportional to the square of distance between them. So, with the relationship that's given to us, i.e 20mm distance->0.5 N Force...We have to make some link. It's given that the point charges exert a force F and distance is given d. If you notice that F is actually the double of 0.5 F, so this means the distance must decrease by 4 times to produce double the force.

ALL made sense.. Thanks man :smile:

Reply 151

klosovic

10

Original post by ayvaak

Posted from TSR Mobile

Thank you again.

Any idea on why this is cos 65 instead of sin 65?

That is sin 65, I think you typed it into your calculator wrong.

Reply 152

Original post by ayvaak

Posted from TSR Mobile

Thank you again.

Why cant you do these calculations in radians as apposed to degrees mode on the calc?

I'm not really sure on that reason tbh. I guess for accuracy purposes maybe. (I'm not 100% sure. Not really very good in Physics Unit 4 lol. )

Reply 153

klosovic

10

Original post by ayvaak

Posted from TSR Mobile

Thank you again.

Why cant you do these calculations in radians as apposed to degrees mode on the calc?

because the angle is measured in degrees

Reply 154

Original post by klosovic

because the angle is measured in degrees

Ahaha. Sorry that was really stupid of me

Posted from TSR Mobile

Anyone have an explanation for why a force is created in the opposite direction to the magnetic field in this question? :smile:

1466183133377.jpg43.8KB

Reply 155

Moe21

6

Can anyone explain to me question 18 (b)(ii) http://qualifications.pearson.com/content/dam/pdf/A%20Level/Physics/2013/Exam%20materials/6PH04_01R_que_20130613.pdf . Isn't max emf induced when the coil is perpendicular (0 degrees on the graph?).
Here is the mark scheme : http://qualifications.pearson.com/content/dam/pdf/A%20Level/Physics/2013/Exam%20materials/6PH04_01R_msc_20130815.pdf

Reply 156

Mowerharvey