Edexcel PHYSICS Doubts

[elemis]

Question 5

Once the lamp in parallel breaks down the total resistance of the circuit will increase, hence, the total current flow will decrease. The PD across L increases whilst the PD across N falls.

Thus, the brightness of L increases and N falls.

Question 6

Power = I²R

W/A² = R   i.e. WA^-2

[The Golden Girl =D]

Paper Attached.

I've got loads of Qs 

hmm can someone explain in section A Qs 4 ,5 , 6

Section B

Qs , 12]b) , 13]a)iii) , 17]b) , 19]a)ii)

Thanks in Advance

Qs 5 and 6 in Section A have been answered but I'd really appreciate it if someone answers the rest 

And I got some more Qs 

Attached QP.

Section A

Qs .4 , 6 .

Ohh when we change from electron volts to Joules  do we Multiply or divide by (1.6 * 10^-19)

Section B

Qs 19]c)i) and ii) , 20]a)iii)

Q 18]c)  I wrote the answer as :  Because ALL the particles of the food will be exposed to micrwaves and get heated up.

is my answer considered correct 

Thanks Again

[elemis]

Question 4

Q=It

The e.m.f of a battery is defined as the work done per unit charge. What is the unit of work ? What other quantity has this unit ?

Got it ?

Question 6

If I tell you that I gained 20 J of useful energy out of a total input of 100 J and I lost 80 J in the process, what would the efficiency be ?

[Banana]

Here are the answers to ur doubts:

19]c)i) :

Well they've said that the spacing between the bands is inversely
proportional to the distance between the two slits. And so use the proportion method (Inverse Variation)

Slit Spacing        Distance between Bands
    1.2mm-------------->0.6mm
    0.4mm-------------->  X

So by finding x, you find the separation distance.....So to find x, dont cross multiply (its not directly proportional, its incersely proportional)

=> 1.2 x 0.6 = 0.4 x X................so X is 1.8mm

19]c)ii)

Okay now they say the slit spacing is increased....using the relationship given (inverse proprtion) an increase in split spacing will decrease the band spacing to the point that they donot overlap at all......thats all you have to say 

20]a)iii)

Lol....I think this question was easy ; they are asking for the power and power is given by P= I x V

So the power in the load is equal to the current in the load multiplied by the pd across the load so multiply the values of D7 and E7.......>

2.14 x 4.29 = 9.18 W


So GG do you get it? If you dont ask again!.....Glad to help....

[The Golden Girl =D]

Thanks Loads Everyone

Ya M&M I get it

[MasterMath]

Isnt the distance between 2 adjacent maxima's a wavelength :S?
Look at 2009 June 20b.. >_>
The distance moved by the microphone between two adjacent maxima is
0.050 m.
Calculate the wavelength of the sound wave.
They say the answer is 0.1 

[elemis]

The distance between 2 adjacent maximas = half a wavelength.

[Malak]

Few doubts:

Q11 (c)
Q16  (b) (never understood polarisation) 

Thankyou very much

[The Golden Girl =D]

Few doubts:

Q11 (c)
Q16  (b) (never understood polarisation) 

Thankyou very much

Q.11]c)

you measure the distance between the compressions let's say it's 4 cm , you move the compressions backwards by 1 cm , I hope you got it ...if not let me know so that I scan my paper

16  (b)

My answer is ;

I would place a Polaroid film and observe .If the intensity decreased it means it might be polarized but I would confirm it by using another Polaroid fiml as an Analyser and rotate it by 90 and observe the intensity of the light ..it would  be darker but not 100 % dark .

I hope you got my idea and excuse my poor representation

[Malak]

I get he second one,
But for Q11, why would you move it backwards by 1 cm 

Thx

[The Golden Girl =D]

I get he second one,
But for Q11, why would you move it backwards by 1 cm  

Thx

I'll ask my friend and get back to you  

EDIT : I copied it from her and she drew it before the compression cuz she though it was a continious wave but well that's not mentioned so it's actually after the first compression by 1 cm

[Malak]

Sorry for being dumb..But why 1 cm ? Is it 'cause the line is t + 3/4 T 

And thx alot

[The Golden Girl =D]

Sorry for being dumb..But why 1 cm ? Is it 'cause the line is t + 3/4 T 

And thx alot

have the four is 2 and then you take the Quarter of that which I guess ain't 1 :S

srry for confusing u

[Malak]

Lol..Its okay...

Thanks for helping though

[The Golden Girl =D]

Lol..Its okay...

Thanks for helping though

Welcome