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Edexcel PHYSICS Doubts

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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:

--- Quote from: The Golden Girl on June 03, 2011, 03:13:03 pm ---Paper Attached.

I've got loads of Qs  :-X

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 :D

--- End quote ---

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  ;D

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.... :D

The Golden Girl =D:
Thanks Loads Everyone :)

Ya M&M I get it :)

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