Incandescent light bulbs consist of an air-tight glass enclosure (the envelope, or bulb) with a filament of tungsten wire inside the bulb, through which an electric current is passed. Contact wires and a base with two (or more) conductors provide electrical connections to the filament.
Answer:
Firstly they are, by design, easy to use in most scientific and engineering calculations; you only ever have to consider multiples of 10. If I’m given a measurement of 3.4 kilometres, I can instantly see that it’s 3′400 metres, or 0.0034 Megametres, or 3′400′000 millimetres. It’s not even necessary to use arithmetic, I just have to remember the definitions of the prefixes (“kilo” is a thousand, “megametre” is a million, “milli” is a thousandth) and shift the decimal point across to the left or the right. This is especially useful when we’re considering areas, speeds, energies, or other things that have multiple units; for instance,
1 metre^2 = (1000millimetre)^2 = 1000000 mm^2.
If we were to do an equivalent conversion in Imperial, we would have
1 mile^2 = (1760 yards)^2
and we immediately have to figure out what the square of 1760 is! However, the fact that SI is based on multiples of 10 has the downside that we can’t consider division by 3, 4, 8, or 12 very easily.
Secondly they are (mostly) defined in terms of things that are (or, that we believe to be) fundamental constants. The second is defined by a certain kind of radiation that comes from a caesium atom. The metre is defined in terms of the second and the speed of light. The kelvin is defined in terms of the triple point of water. The mole is the number of atoms in 12 grams of carbon-12. The candela is defined in terms of the light intensity you get from a very specific light source. The ampere is defined using the Lorentz force between two wires. The only exception is the kilogram, which is still defined by the mass of a very specific lump of metal in a vault in France (we’re still working on a good definition for that one).
Thirdly, most of the Imperial and US customary units are defined in terms of SI. Even if you’re not personally using SI, you are probably using equipment that was designed using SI.
Answer: Option (C) is the correct answer.
Explanation:
Whether an acid is weak or strong it will cause harm if it comes in direct contact with the skin, eyes or mouth etc.
Thus, in order to prevent oneself, it is advised to wear a lab coat while working in laboratory as acids break down fabrics and can cause burns if the acids are strong.
Hence, a lab coat acts as a protective layer on the clothes so that even if acid falls on it then it might not reach the skin immediately and on time prevention can be taken.
Answer:
h= 45.87 m.
Explanation:
Data given:
Vf= 30m/s , and we know that g = 9.8 m/s²
The ball has an initial velocity of zero Vi = 0 m/s²
To Find:
Height of the building = ?
Solution:
According to 3rd law of the motion;
2aS= Vf² - Vi² ( S= h , a=g)
2*9.81*h = (30)² - (0)²
h= 45.87 m.
Reflection-----------------------------
