Answer:
The depth of focus achievable with those lenses is small.
Explanation:
A larger aperture makes it much harder to focus on more than one object. When using a telephoto lens (the ones the question is referring to), the depth of focus is very small. For example, using a telephoto lens to take a photo of a runner might get the runner in focus, but certainly not the track, or the audience behind them. If you look at photos, especially older photos, of Olympians in almost any sport you can see this.
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Answer:
The radius of the disc is 2.098 m.
(e) is correct option.
Explanation:
Given that,
Moment of inertia I = 12100 kg-m²
Mass of disc m = 5500 kg
Moment of inertia :
The moment of inertia is equal to the product of the mass and square of the radius.
The moment of inertia of the disc is given by

Where, m = mass of disc
r = radius of the disc
Put the value into the formula



Hence, The radius of the disc is 2.098 m.
S.I. Unit of mass is Kilogram which is denoted by Kg
In short, Your Answer would be Option C
Hope this helps!
True because school doesn't dictate what job you want in the future