# OCR Physics A G485 - Frontiers of Physics - 18th June 2015Watch

3 years ago
#1181
what is definition for 1 parsec?
3 years ago
#1182

what is question?
If capacitors of different capacitance were in parallel would they still discharge at the same rate. Or because the current through them is different the one with the greater capacitance discharges faster?
0
3 years ago
#1183
(Original post by buxtonarmy)
Thanks bro so how would I do 4bi on this paper? It's similar and I still struggle

http://www.ocr.org.uk/Images/65365-q...of-physics.pdf
0.15 x speed of light

Use the change in wavelength formula
0
3 years ago
#1184

what is definition for 1 parsec?
distance that gives a parallax angle of 1arcsecons
0
3 years ago
#1185

what is definition for 1 parsec?
The distance from the baseline of 1AU that subtends an angle of 1 arc second.
0
3 years ago
#1186
(Original post by kate8)
If capacitors of different capacitance were in parallel would they still discharge at the same rate. Or because the current through them is different the one with the greater capacitance discharges faster?
Where RxC the resistance will decrease if put in parallel.... hence the time constant increases this means that the rate of change of V,Q or I must decrease as a larger time to fall to 1/e of its initial value hence the initial rate of discharge will decrease

Oops sorry thought you said resistance, capacitors work the same way, if put in parallel, total capacitance increases to larger time constant same explanation
0
3 years ago
#1187
(Original post by jamesbird18)
Can somebody please help me? If we get a question that involves,say a proton moving from left to right would you say the current is moving left to right or not? Could alter any answer using FLHR thats all
The current flows in the same direction as the protons and opposite to electrons.
0
3 years ago
#1188
(Original post by Chung224)
Where RxC the resistance will decrease if put in parallel.... hence the time constant increases this means that the rate of change of V,Q or I must decrease as a larger time to fall to 1/e of its initial value hence the initial rate of discharge will decrease
that makes no sense to me
0
3 years ago
#1189
(Original post by ForgottenApple)
that makes no sense to me
Which part bro?
0
3 years ago
#1190
Can someone explain how I got from
s-1 Hubbles constant to
kms-1 Mpc-1
3 years ago
#1191

what is definition for 1 parsec?
The distance that gives a stellar parallax 1 second of arc.
0
3 years ago
#1192
(Original post by ETRC)
-intensifier absorbs x-rays by photographic film
-scintillator is used as an intensifier
-scintillator converts x-ray photon into many photons of visible light
-photons of visible light releases electrons so a lower exposure time to x-rays is needed
-gives a sharper images
Hey do you know which has greater energy - a pair production x ray or a compton effect x ray?
0
3 years ago
#1193

Can someone explain how I got from
s-1 Hubbles constant to
kms-1 Mpc-1
Still on 2010?
0
3 years ago
#1194
(Original post by Chung224)
Where RxC the resistance will decrease if put in parallel.... hence the time constant increases this means that the rate of change of V,Q or I must decrease as a larger time to fall to 1/e of its initial value hence the initial rate of discharge will decrease

Oops sorry thought you said resistance, capacitors work the same way, if put in parallel, total capacitance increases to larger time constant same explanation
If the resistance decreases shouldn't the time constant...?
0
3 years ago
#1195
(Original post by nothepreacher)
Hey do you know which has greater energy - a pair production x ray or a compton effect x ray?
pair production x-ray has the highest frequency, E= hf so id say the pair production x-ray
0
3 years ago
#1196
(Original post by Smug Life)
Still on 2010?
What do you mean?
3 years ago
#1197
(Original post by randlemcmurphy)
If the resistance decreases shouldn't the time constant...?
yeah thats what i was thinking: t is proportional to C and R so if C decreases so much t
0
3 years ago
#1198
could someone show me what a good drawing is for the definition of a parsec? (has the sun, earth, star, AU in!)
0
3 years ago
#1199
(Original post by nothepreacher)
Hey do you know which has greater energy - a pair production x ray or a compton effect x ray?
pair production is highest- they involve high energy x-rays being released

then its compton

photoelectrons from photoelectric have least energy

my brain hurts now from revising for 7 hours with a 30min break -.-
0
3 years ago
#1200
(Original post by stargazer678)
could someone show me what a good drawing is for the definition of a parsec? (has the sun, earth, star, AU in!)
June 2013 Q10
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