Answer:
The focal length of eye piece is 6.52 cm.
Explanation:
Given that,
Angular Magnification of the microscope M = -46
the distance between the lens in microscope L= 16 cm
The focal length of objective f₀ = 1.5 cm
Normal near point N = 25 cm
Have to find focal length of eye piece f ₙ =?
The angular magnification is given by
M ≈ - (L-fₙ)N/f₀fₙ
Rearranging for fₙ
fₙ =L(1 - Mf₀/N)⁺¹
=18/2.76
fₙ = 6.52 cm
The focal length of eye piece is 6.52 cm.
Before a person walks through burning coal, the person will make sure their feet are very wet. When they start walking on the coal, this moisture will evaporate and form a protective gas layer underneath the person's feet. You can see examples of this if you happen to drip some water on a hot stove or any very hot surface. The water will very easily glide around on top of a newly formed layer of air underneath it -- like air hockey pucks on an air hockey table. Note that when someone walks through burning coal, typically this is also done very quickly to prevent a great deal of exposure to possible harm. By walking quickly, thinking positively, and letting the water cushion you from immediate danger over a short distance, such a task is possible. You may have also heard of physics teachers demonstrating how this principle works by sticking their hand first in a bucket of water and then quickly in a bucket of boiling molten lead. In the lead, their hand is protected briefly by a layer of gas from the evaporated water (the water vapor). I'm fairly sure that there is a name for this particular layer of gas, but I'm afraid the name is beyond me at the moment. In other words, water vapor has a low heat capacity and poor thermal conduction. Very often, the coals or wood embers that are used in fire walking also have a low heat capacity. Sweat produced on the bottom of people's feet also helps form a protective water vapor. All of this together makes it possible, if moving quickly enough, to walk across hot coals without getting burned. WARNING: Do not attempt to perform any of the actions described above. You can seriously injure yourself. Answered by: Ted Pavlic, Electrical Engineering Undergrad Student, Ohio St. (citing my source)
Answer: conductors are substances that allow heat or electricity to pass through . It deals with only the flow of electrons.
Eg. water, copper wire, iron rod, some ceramic materials, metallic nail.
Insulators are materials that do not allow heat or electricity to pass through.
Eg. Book, plastic, rubber, glass, paper
Explanation:
To keep the energy going every day
Answer
given,
heat added to the gas,Q = 3300 kcal
initial volume, V₁ = 13.7 m³
final volume, V₂ = 19.7 m³
atmospheric pressure, P = 1.013 x 10⁵ Pa
a) Work done by the gas
W = P Δ V
W = 1.013 x 10⁵ x (19.7 - 13.7)
W = 6.029 x 10⁵ J
b) internal energy of the gas = ?
now,
change in internal energy
Δ U = Q - W
Q = 3300 x 10³ cal
Q = 3300 x 10³ x 4.186 J
Q = 1.38 x 10⁷ J
now,
Δ U = 1.38 x 10⁷ - 6.029 x 10⁵
Δ U = 1.32 x 10⁷ J
