[cisne]

(Original post by Parthenon93)
The parallax angle to Barnard's star is 0.545''. How far away is the star in metres?

I get 5.68 x 10^16m, but the answer given is 1.14 x 10^17m.

Please help?

may be the answer given is wrong...i dont know...
i mean this is how it should be done,...right???

parallex angle = 0.545

1" = 1/3600
0.545" = x
x = 1.51x10^-4

d=r/tan(theta)
d= (1.5x10^-4) / tan(1.51x10^-4)
d= 5.69x10^16 m


please someone correct me if I'm wrong....

[cisne]

(Original post by King_Arthur)
if only i can get hold of these notes ...
http://www.educationusingpowerpoint...._Collapse.html

arrghhh! have to pay???? i don't have a credit card

[King_Arthur]

(Original post by Parthenon93)
The parallax angle to Barnard's star is 0.545''. How far away is the star in metres?

I get 5.68 x 10^16m, but the answer given is 1.14 x 10^17m.

Please help?

you have divide the angle by 2 u haven't done that

workings

d=(1.5/10^11)/tan(.545/(2*3600))
= 1.4*10^17

do u want further explanation ??????????????????????

[King_Arthur]

(Original post by cisne)
may be the answer given is wrong...i dont know...
i mean this is how it should be done,...right???

parallex angle = 0.545

1" = 1/3600
0.545" = x
x = 1.51x10^-4

d=r/tan(theta)
d= (1.5x10^-4) / tan(1.51x10^-4)
d= 5.69x10^16 m


please someone correct me if I'm wrong....

ur wrong i have posted the correct workings

[cisne]

(Original post by King_Arthur)
ur wrong i have posted the correct workings

thanks...my teacher marked it as a right answer

[King_Arthur]

(Original post by cisne)
thanks...my teacher marked it as a right answer

small correction
but weather to divide the angle depends in what angle they have given i assumed that the angle given was double the parralex angle as measure in a gap of 6 months just to clarify was this a past paper question so i can confirm my assumption

[Parthenon93]

(Original post by King_Arthur)
small correction
but weather to divide the angle depends in what angle they have given i assumed that the angle given was double the parralex angle as measure in a gap of 6 months just to clarify was this a past paper question so i can confirm my assumption

It is the Miles Hudson book page 191.

I'll copy the exact question:

The parallax angle to Barnard's star is 0.545". How far away is Barnard's star in a. metres b. light years c. parsecs d. astronomical unit

It did not mention "after 6month period". How do we know when to divide and when not to divide?

[TheGrinningSkull]

(Original post by iesians)
why is iron the end product of all fusion and fission reactions ..?!

Maybe someone's already answered this but it's the most stable nucleus with the highest binding energy per nucleon.

EDIT: It also has the lowest possible energy state.

[Parthenon93]

(Original post by TheGrinningSkull)
Maybe someone's already answered this but it's the most stable nucleus with the least binding energy per nucleon.

Shouldn't it be the highest binding energy per nucleon, therefore most stable?

[King_Arthur]

(Original post by Parthenon93)
It is the Miles Hudson book page 191.

I'll copy the exact question:

The parallax angle to Barnard's star is 0.545". How far away is Barnard's star in a. metres b. light years c. parsecs d. astronomical unit

It did not mention "after 6month period". How do we know when to divide and when not to divide?

no in this case ur workings seems correct who told u it's wrong

[cisne]

(Original post by Parthenon93)
It is the Miles Hudson book page 191.

I'll copy the exact question:

The parallax angle to Barnard's star is 0.545". How far away is Barnard's star in a. metres b. light years c. parsecs d. astronomical unit

It did not mention "after 6month period". How do we know when to divide and when not to divide?

good question....i'll get mad before 22nd june if things are going same like this

[Parthenon93]

Can anybody do a quick differenence between brightness, luminosity, intensity and radiation flux for me?

This is what I am on ...

Brightness = Radiation flux and is how much of the emitted energy we (at a certain distance away) from the black body.

Luminosity = Power and is the rate at which energy is emitted from the surface of the black body.

I don't know where to put intensity in all this.

[King_Arthur]

Power per unit area is intensity

luminosity total power emitted

[Parthenon93]

(Original post by King_Arthur)
Power per unit area is intensity

luminosity total power emitted

So brightness/radiation flux is the intensity?

[Parthenon93]

(Original post by King_Arthur)
Power per unit area is intensity

luminosity total power emitted

Could you please convert 1.4 x 10^17m to light years and parsecs for me? I think I am getting the wrong answers.

[TheGrinningSkull]

(Original post by Parthenon93)
Shouldn't it be the highest binding energy per nucleon, therefore most stable?

You're right, I got confused there, thanks for the correction.

Why is it sometimes you get the same graph inverted? It's really confusing when they invert it and you see the same y-axis label.

Maybe it was the one-off graph I seem to have seen or a bad label.

[cisne]

(Original post by Parthenon93)
Could you please convert 1.4 x 10^17m to light years and parsecs for me? I think I am getting the wrong answers.

is this correct??

1 LY = 9.46x10¹⁵m
d=1.4x10¹⁷/ 9.46x10¹⁵
d=14.8 LY


1pc = 3.26 LY
x pc= 14.8 LY
x= 4.53 pc


1AU = 1.5x10¹¹m
x AU= 1.4x10¹⁷
x = 9.33x10⁵ AU
???????????????????????????????? ???????

[Killjoy-]

(Original post by Parthenon93)
Shouldn't it be the highest binding energy per nucleon, therefore most stable?

You are correct there.

[Parthenon93]

(Original post by cisne)
is this correct??

1 LY = 9.46x10¹⁵m
d=1.4x10¹⁷/ 9.46x10¹⁵
d=14.8 LY


1pc = 3.26 LY
x pc= 14.8 LY
x= 4.53 pc


1AU = 1.5x10¹¹m
x AU= 1.4x10¹⁷
x = 9.33x10⁵ AU
???????????????????????????????? ???????

Those are the exact answers I get The answer scheme says otherwise ... 12ly and 3.68pc ... I am beginning to think the answers are effed for this question.

I had this other question, where they said billion but considered million.

[cisne]

(Original post by Parthenon93)
Those are the exact answers I get The answer scheme says otherwise ... 12ly and 3.68pc ... I am beginning to think the answers are effed for this question.

I had this other question, where they said billion but considered million.

owh.....is there anybody else who'd like to try this,...please???