[H]Physics mirrors...

YPang

United States4024 Posts

May 05 2009 00:36 GMT

It is observed that the size of a real image formed by a concave mirror is two times the size of object when the object is 32.0 cm in front of the mirror. What is the radius of curvature of this mirror?

So what i did was first used magnify= - d image / d original

m= -2/1= di/32. <--- I solved for di which was = -64. Then i plugged it in to this equation...

(1/di)+(1/do)=(1/focus). So i got (1/32)+(1/-64)=(1/f) :: Focus= 64.

I plugged that number in it was wrong, so i thought maybe they wanted the radius that was double the focus, so i put 128, and it was also wrong. BTW everything is in cm, and they want the answer in cm, so i didn't conver to meters.

micronesia

United States24745 Posts

May 05 2009 01:02 GMT

While I'm typing it up note that you should probably neglect the negative sign in m = -di/do since it's a convention to show inverted...

Givens:

Object Height = x
Image Height = 2x (note my choices)
Object distance = 32 and must be placed in between F and C since the image is magnified (see wikipedia)

m = hi/ho

m = 2x/x = 2 ***

m = -di/do
m = di/do <--- I think we neglect the negative
2 = di/32
di = 64 ***

1/do + 1/di = 1/f
1/32 + 1/64 = 1/f
Solve and get f = 64/3
Double because you want C, not F and you get 128/3

Does that work?

YPang

United States4024 Posts

May 05 2009 01:48 GMT

yes thanks man!!!!!!!!!!

i need to buy you a neew car...

Archaic

United States4024 Posts

May 05 2009 02:40 GMT

Why does YPang get micronesia's help T_T. Luckily, I managed to succeed in the retake without the glorious micronesia. Next time though...

micronesia

United States24745 Posts

May 05 2009 04:03 GMT

On May 05 2009 11:40 Archaic wrote:
Why does YPang get micronesia's help T_T. Luckily, I managed to succeed in the retake without the glorious micronesia. Next time though...

http://www.teamliquid.net/blogs/viewblog.php?topic_id=91951#2

I am the first reply in every physics blog on teamliquid. What are you complaining about?

Please or register to reply.

[H]Physics mirrors...

Completed

Ongoing

Upcoming