The same power (1.9×10^4 watts) gets diminished by Inverse square law
<span>(ratio of distances)² </span>
<span>= (138/70000)² </span>
<span>= 3.886506 X 10^-6 . </span>
<span>This is the diminution factor for the given sensitivity of the telescope. But at 3.8865 millionth below the sensitivity its is far below detection; it needs to be enhanced by collecting the energy over an area so many times more (by an aperture multiplied by same factor) </span>
<span>1/[3.886506 X 10^-6] = 257298.88 </span>
<span>In other words the diameter should have the ratio of square root of this </span>
<span>(70000/138). </span>
<span>This multiplied by 300m dish gives </span>
<span>300 X (70000/138) = 152173.913 m = 152.1739 km. </span>
<span>This should be the aperture of the new telescope for detecting the signal.</span>
Answer: f = 927.55Hz
Explanation: Since the the tube is open-closed, the length of air and the wavelength of sound passing through the tube is given below
L = λ/4 where λ = wavelength.
speed of sound in air = v = 343m/s.
fundamental frequency of open closed tube = 315Hz
λ = 4L.
v = fλ
343 = 315 * 4L
343 = 1260 * L
L = 343/ 1260
L = 0.27m
In the same tube of length L = 0.27m but different medium ( helium), the speed of sound is 1010m/s.
The length of tube and wavelength are related by the formulae below
L = λ/4, λ=4L
λ = 4 * 0.27
λ = 1.087m.
v = fλ
1010 = f * 1.087
f = 1010/1.807
f = 927.55Hz
The answer is C, an educated guess
Answer:
A)mirror.
Explanation:
To read what DaVinci wrote, one has to use a mirror. This style of writing is known as mirror writing.
A mirror is an optical instrument that has smooth surface and can reflect light to form an image.
- When a mirror is placed in front of the image, it will show clearly and readable.
- Mirror images laterally inverts a text and will make the text normal again.
Answer:
Explanation:
As we know that the mass is revolving with constant angular speed in the circle of radius R
So we will have
now the position vector at a given time is
now the linear velocity is given as