Posted by mark on Wednesday, April 11, 2012 at 10:35pm.
Where must an object be placed to have a
magniﬁcation of 3.74 in front of a converging
lens of focal length 14.1 cm?

physics  drwls, Wednesday, April 11, 2012 at 10:51pm
Let do be the object distance and di be the image distance.
di/do = 3.74, the magnification.
1/do + 1/di = 1/do + 1/(3.74 do)
= 4.74/(3.74 do)
= 1.267/do = 1/14.1
Solve for do.

Physics  John, Thursday, April 12, 2012 at 8:48pm
Three identical small Styrofoam balls of mass
1.53 g are suspended from a ﬁxed point by
three nonconducting threads, each with a
length of 56.4 cm and negligible mass. At
equilibrium the three balls form an equilateral triangle with sides of 31 cm.
What is the common charge carried by
each ball? The acceleration of gravity is
9.8 m/s
2
and the value of Coulomb’s constant
is 8.98755 × 10
9
N · m2
/C
2
.
Answer in units of µC
Answer This Question
Related Questions
 Physics  Where must an object be placed to have a magniﬁcation of 3.74 ...
 physics  Hi! could any help me please, thank you. 1.An object is placed 17.8 cm...
 Physics  A lighted candle is placed 38 cm in front of a diverging lens. The ...
 Physics  two lenses,one converging with focal length 20.0 cm and one diverging ...
 physics  Please, anyone help me please. Q: An object is placed 17.8 cm from a ...
 Physics  Two converging lenses are placed 31.0 cm apart. The focal length of ...
 physics  Two converging lenses, having focal length 5 cm and 10 cm respectively...
 physics  The Yerkes refracting telescope has a 1 m diameter objective lens of ...
 Physics 2  A converging lens with a focal length of 19 cm is used to form an ...
 Science Important  1. A toy of height 18.4 cm is balanced in front of a ...
More Related Questions