The image distance when a boy holds a toy soldier in front of a concave mirror, with a focal length of 0.45 m. is -0.56 m.
<h3>What is image distance?</h3>
This is the distance between the image formed and the focus when an object is placed in front of a plane mirror.
To calculate the image distance, we use the formula below.
Formula:
- 1/f = 1/u+1/v........... Equation 1
Where:
- f = Focal length of the mirror
- v = Image distance
- u = object distance
From the question,
Given:
Substitute these values into equation 1 and solve for the image distance
- 1/0.45 = 1/0.25 + 1/v
- 2.22 = 4+1/v
- 1/v = 2.22-4
- 1/v = -1.78
- v = 1/(-1.78)
- v = -0.56 m
Hence, The image distance is -0.56 m.
Learn more about image distance here: brainly.com/question/17273444
D. The graduated cylinder is used to find the volume, and triple beam balance is used to find the mass.
<span>Convert angstroms to nm for atom diameter
2.18/10=.218 nm. Divide diameter by length width and height.
63.6/.218=292
74.2/.218=327
275/.218=1261
Multiply these to get volume of atoms
120,037,500
Convert atoms to moles using Avogadro number
120,037,500/6.02*10^23=2*10^-16 moles</span>
