Answer:
The objective lens is an optical tool used to focus an image.
Explanation:
The objective lens is an optical tool that collects light emitted by an object under observation and focuses the rays of light in order to form a real and magnified image They are used in optical instruments like microscopes, cameras, telescopes, etc. and are also referred as objective or object glasses.
Answer:
The value is 
Explanation:
From the question we are told that
The focal length of the objective is 
The focal length of the eyepiece is 
The tube length is 
Generally the magnitude of the overall magnification is mathematically represented as

Where
is the objective magnification which is mathematically represented as

=> 
=> 
is the eyepiece magnification which is mathematically evaluated as



So


Astronomers find white dwarfs that distinguish them from main sequence stars because white dwarfs get really hot, we can search for their ultraviolet radiation.
<h3>What is a white dwarf?</h3>
A white dwarf is a very hot star that radiated much energy in the form of ultraviolet radiation.
This UV radiation is initially very bright and then these stars become red with time.
In conclusion, Astronomers find white dwarfs they can search for their ultraviolet radiation.
Learn more about white dwarfs here:
brainly.com/question/19602278
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Answer:
Copper
Explanation:
Since the heat of Fussion of copper is less than that for nickel it means copper melts faster than nickel.
Answer: m= 2.16 kg
Explanation: Momentum is expressed in the following formula:
p = mv
Derive to find m:
m = p / v
= 4.75 kg.m/s / 2.2 m/s
= 2.16 kg
Cancel out m/s and the remaining unit is in kg.