The other 4 kg of mass may have departed the scene
of the fire, in the form of gases and smoke particles.
Answer:

Explanation:
Given that
For straight wire
Charge density= λ
For hollow metal cylinder
Charge density=2 λ
We know that electric filed for wire given as


Now the electric filed due to hollow metal cylinder


Now by considering the Gaussian surface r<R then only electric fild due to wire will present.So
At r<R

Parfocal is the term used to describe a microscope that maintains focus when the objective lenses are replaced.
<h3>
What is the name of the objective lens ?</h3>
For observing minute features within a specimen sample, a high-powered objective lens, often known as a "high dry" lens, is perfect. You can see a very detailed image of the specimen on your slide thanks to the 400x total magnification that a high-power objective lens and a 10x eyepiece provide.
The four objective lenses on your microscope are for scanning (4x), low (10x), high (40x), and oil immersion (100x).
The first-stage lens used to create a picture from electrons leaving the specimen is referred to as the "objective lens." The objective lens is the most crucial component of the imaging system since the quality of the images is determined by how well it performs (resolution, contrast, etc.,).
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Answer:
Balances and Scales
A balance compares an object with a known mass to the object in question. One example of a balance is the triple beam balance. The standard unit of measure for mass is based on the metric system and is typically denoted as kilograms or grams.