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Answer: a.The mirrors and eyepiece of a large telescope are spring-loaded to allow them to return quickly to a known position. </h2>
Explanation:
Adaptive optics is a method used in several astronomical observatories to counteract in real time the effects of the Earth's atmosphere on the formation of astronomical images.
This is done through the insertion into the optical path of the telescope of sophisticated deformable mirrors supported by a set of computationally controlled actuators. Thus obtaining clear images despite the effects of atmospheric turbulence that cause the unwanted distortion.
It should be noted that with this technique it is also necessary to have a moderately bright reference star that is very close to the object to be observed and studied. However, it is not always possible to find such stars, so a powerful laser beam is used to point towards the Earth's upper atmosphere and create artificial stars.
Distance = (speed) x (time)
Distance = (0.5 m/s) x (2.3 s)
Distance = (0.5 x 2.3) m
Distance = 1.15 meters
Answer:

Explanation:
Let the distance moved by Joe is "d"
so the time taken by him to drove it by speed 45 mph is given as


now the same distance is traveled by him with speed 55 mph
so the time taken by him

so total time taken by him for complete distance 2d



now the average speed is given as



Answer:
c. The steady-state value of the current depends on the resistance of the resistor.
Explanation:
Since all the components are connected in series, when the switch is at first open, current will not flow round the circuit. As current needs to flow through from the positive terminal of the battery through the resistor, inductor, and switch to the negative terminal of the battery.
But the moment the switch is closed, at the initial time t = 0, the current flow through from the positive terminal of the battery through the resistor, inductor, and switch to the negative terminal of the battery. It then begins to increase at a rate that depends upon the value of the inductance of the inductor.