The white disks in the petri plates are soaked in herbicide, which affects the roots, stalks, leaves, and cobs of a corn plant.
1 answer:
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From the concept of optics on a curvature of a spherical mirror, the proportion for which the focal length is equivalent to half the radius of curvature is fulfilled. Mathematically this is
Here,
f = Focal Length
R = Radius
Rearranging to find the radius we have,
Replacing with our values,
R = 2(13.8cm)
R = 27.6cm
Therefore the radius of the spherical surface from which the mirror was made is 27.6cm
Answer:
i) 21 cm
ii) At infinity behind the lens.
iii) A virtual, upright, enlarged image behind the object
Explanation:
First identify,
object distance (u) = 42 cm (distance between object and lens, 50 cm - 8 cm)
image distance (v) = 42 cm (distance between image and lens, 92 cm - 50 cm)
The lens formula,
Then applying the new Cartesian sign convention to it,
Where f is (-), u is (+) and v is (-) in all 3 cases. (If not values with signs have to considered, this method that need will not arise)
Substituting values you get,
i)
f = 21 cm
ii) u =21 cm, f = 21 cm v = ?
Substituting in same equation
v ⇒ ∞ and image will form behind the lens
iii) Now the object will be within the focal length of the lens. So like in the attachment, a virtual, upright, enlarged image behind the object.
