You asked the question twice I answered it on the last one
D.) White Dwarf
It is the smallest star whose mass is approximately equal or greater than 1.4M
Here, M = mass of the Sun.
Hope this helps!
<span>The particles in a gas are apart and moving fast, so the forces of attraction are too weak to have a noticeable effect.</span>
As we know that in transformers we have

here we know that




now from above equation we will have


now we have to reduce this voltage to final voltage of V = 4 V
so again we will have



so we need to take such a winding whose ratio is 1:5
So it is satisfied in X


so answer will be
<u>B)- X</u>
Answer:
630 Hz.
Explanation:
As we are considering the one end open pipe. So for the sound wave there will be a pressure node at the open end of the tube as at that place the molecules can not move back and forth. However on the closed end there will be a flow node as the water molecules their are moving back and forth. So it will produces the resonance at the positions 1/4, 3/4.......
we can find the wavelength by multiplying the levels distance by 2.
λ = 2 × 0.27 m = 0.54
f = Vs/λ
= 340/0.54
= 630 Hz