Answer:
the dimensions of the rectangle are:
l = 50 m
b =
Solution:
As per the question:
Perimeter of the room, P = 200 m
The region is rectangular having a semicircle at each end.
Now,
Let 'l' be the length of the rectangle, 'b' be its breadth and 'r' be the radius of the semi-circle at each end.
Then
Area of the rectangle, A = lb
Perimeter of the room, P =
Therefore, we can write:
Now,
Area, A =
Now, differentiate A w.r.t l:
Again differentiating w.r.t 'l', we get:
< 0
Thus we get maximum are when
Therefore,
l = 50 m
Now, from
b =
r =
Choice-D is the correct one.
For the solution, see my detailed response
to the other posting of the same question.
Answer:
Black holes are detected as surrounding material (like gas) is funnelled by the force of gravity into a disk around the black hole. The gas molecules in the disk swirl around the black hole so fast that they heat up and emit X-rays. These X-rays can be detected from Earth.
Explanation:
Answer:
Explanation:
Given
Speed of Primary wave
Speed of secondary wave
difference in timing of two waves are
Suppose both travel a distance of d km then
Subtract (ii) from (i)
Answer:
Part A: D
Part B: W = Qh - Qc
Part C: e = 1 - Qc/Qh
Explanation:
The heat engine is the engine that transforms heat (Q) in work (W), and by the second law of the thermodynamics, its efficiency can not be 100%, it means that some heat must be dissipated.
Part A:
The engine works with two sources of heat, one hot (Qh) at a hot temperature (Th) and another cold (Qc) at a cold temperature (Tc). It is necessary so, the hot source will give energy to the fluid of the engine, and the cold source will be the source where these heat will dissipate and the fluid will return to its original temperature. So,
Qh > Qc, and Th > Tc
Part B:
The ideal heat engine is the one that can use the most amount of heat to transform it at work. It is characterized by Qh/Qc = Th/Tc.
The work is the useful energy, so it is the total heat (Qh) less the heat dissipated (Qc):
W = Qh - Qc
Part C:
The effiency is the useful energy divided by the total energy. Because W = Qh - Qc:
e = W/Qh
e = (Qh - Qc)/Qh
e = Qh/Qh - Qc/Qh
e = 1 - Qc/Qh