The
correct answer to this would be letter:
A. Earth’s volcanoes
Together with weathering and plate tectonic movements, Earth’s
volcanic eruptions and emission of lava has destroyed/covered many of the craters which
were created on Earth during the Period of Heavy Bombardment.
Answer:
114.26
Explanation:
a)Formula for per unit impedance for change of base is
Zpu2= Zpu1×(kV1/kV2)²×(kVA2/kVA1)
Zpu2: New per unit impedance
Zpu1: given per unit impedance
kV1: give base voltage
kV2: New bas votlage
kVA1: given bas power
kVA2: new base power
In the question
Zpu2=??
Zpu1= 0.3
kV2=24kV
kV1= 13.8 kV
kVA2= 1MVA ×1000= 1000 kVA
kVA1=500kVA
Zpu2= 0.3(13.8/24)²×(1000/500)
Zpu2= 0.198
b) to find ohmic impedance we will first calculate base value of impedance(Zbase). So,
Zbase= kV²/MVA
Zbase= 13.8²/(500/1000)
Zbase=380.88
Now that we have base value of impedance, Zbase, we can calculate actual ohmic value of impedance(Zactual) by using the following formula:
Zpu=Zactual/Zbase
0.3= Zactual/380.88
Zactual= 114.26 ohms
Explanation:
It is given that,
Mass of platinum bar, m = 750 g
Length of the bar, l = 5 cm
Breadth of the bar, b = 4 cm
Width of the bar, h = 1.5 cm
Volume of the bar, 
We need to find the density of the platinum bar. The density of any substance is given by :
So, the density of the platinum bar 
. Hence, this is the required solution.
Answer:
A pipe open at both ends would have an antinode at each end and its length would be λ/ 2
The next such points would be λ and 3 λ / 2
The ratio of 522 / 348 is 1.5 so the harmonic at 348 is one wavelength and the next harmonic is 3 λ / 2 at 1 1/2 wavelengths
348 hz would occur at one wavelength
f λ = v = f L where the length of the pipe is one wavelength
if we use 331 as the speed of sound then
L = 331 / 348 = .95 m for the length of the pipe
