Qualification > Sciences
ALL PHYSICS DOUBTS - POST HERE !!
ambitious94:
--- Quote from: thenewkid™ on May 26, 2010, 04:44:33 pm ---yes its the same 1
i can even draw the diagram
--- End quote ---
guys what's all the fuss about. It isnt even the same thing n ur makin it kinda obvious!
The answer is B.
N I solved this question in a pastpaper myself! (Bet u all did XD) :D
Ivo:
--- Quote from: ambitious94 on May 26, 2010, 04:49:48 pm ---guys what's all the fuss about. It isnt even the same thing n ur makin it kinda obvious!
The answer is B.
N I solved this question in a pastpaper myself! (Bet u all did XD) :D
--- End quote ---
Is it because first time, it attracts. But when current is reversed, steel is magentically hard so hangs on to magnetism, so it repels, cos if forms poles?
Shazizzzle:
--- Quote from: Raywin on May 26, 2010, 04:46:25 pm ---Hey guys... doubt. O/N 08 Q 5(c) :/ The paper doesnt open for some reason. So heres the Q
Using a 40w heater, 16.3g of ice is melted in 2.0 minutes. The heater is then switched off. In a further 2.0 minutes, 2.1g of ice is melted. Calculate the value of the specific latent heat of fusion of ice from these results.
--- End quote ---
Using the formula for latent heat, P X T = mL, we can find the spc. lt. ht.
Now, 16.3 g was melted USING THE HEATER.
Without the heater, 2.1g of ice melted in the same. That was due to the heat from surroundings!
So, for the mass the heater itself melted= heater - without heater
= 16.3 - 2.1
=14.2
time= 2 min = 60 x 2 = 120 s
Now, p X t = mL
40 X 120 = 14.2 X L
4800/14.2 = L
L= 338.028
thus, L = 338 J/g
Shazizzzle:
So... What're you guys doing for Paper 3?
We obviously cannot complete the entire syllabus in one day.
Raywin:
--- Quote from: Shazizzzle on May 26, 2010, 04:56:23 pm ---Using the formula for latent heat, P X T = mL, we can find the spc. lt. ht.
Now, 16.3 g was melted USING THE HEATER.
Without the heater, 2.1g of ice melted in the same. That was due to the heat from surroundings!
So, for the mass the heater itself melted= heater - without heater
= 16.3 - 2.1
=14.2
time= 2 min = 60 x 2 = 120 s
Now, p X t = mL
40 X 120 = 14.2 X L
4800/14.2 = L
L= 338.028
thus, L = 338 J/g
--- End quote ---
Wait. I thot the Q said that AFT 16.3g of ice is melted the heater is turned off.. so why r we subtracting 2.1 from 16.3?? Thts wht i dont get!! Thx a lot! :)
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