Heat lost or gained, H = mc(θ₂ - θ₁)
Where m = mass, c = Specific heat capacity, θ₂= final temperature, θ₁ = initial temperature
m = 200g, c = 0.444 J/g°C, θ₁ = 22 °C (Since it was cooled).
H = 6.9 kj = 6.9 *1000J = 6900 J
6900 = 200*0.444* (θ₂ - 22)
6900/(200*0.444) = θ₂ - 22
77.70 = θ₂ - 22
θ₂ - 22 = 77.7
θ₂ = 77.7 + 22 = 99.7
So initial temperature before cooling ≈ 100°C . Option C.
Answer:
Very hot during the day and very cold at night.
Explanation:
Due to the thin atmosphere, they have very hot climate during the day time and very cold climate at night. This happens because they contain very low amounts of greenhouse gases. These gases retain the heat at night. The atmosphere also prevents excessive light and UV rays from entering. The thin atmosphere leads to many asteroids and comets hitting the surface of the planet. On earth, these asteroids usually, burn up in the mesosphere layer of the atmosphere. These asteroid collisions cause massive fires. This in turn, causes the temperature to increase during the day. During the night time, massive fires cannot burn due to the low temperature because of the lack of greenhouse gases.
Radiation damages the cells that make up the human body, it can even cause cancer
Answer:
9.25 x 10^-4 Nm
Explanation:
number of turns, N = 8
major axis = 40 cm
semi major axis, a = 20 cm = 0.2 m
minor axis = 30 cm
semi minor axis, b = 15 cm = 0.15 m
current, i = 6.2 A
Magnetic field, B = 1.98 x 10^-4 T
Angle between the normal and the magnetic field is 90°.
Torque is given by
τ = N i A B SinФ
Where, A be the area of the coil.
Area of ellipse, A = π ab = 3.14 x 0.20 x 0.15 = 0.0942 m²
τ = 8 x 6.20 x 0.0942 x 1.98 x 10^-4 x Sin 90°
τ = 9.25 x 10^-4 Nm
thus, the torque is 9.25 x 10^-4 Nm.
<em>Anything</em> that's dropped through air is somewhat affected by air resistance. But, out of that list, the leaf and the balloon are the items that will be affected by air resistance enough so that you can plainly see it.
If you spend some time thinking about it, you can kind of understand why airplane wings and boat propellers are shaped more like leafs and balloons than like bricks and rocks.
