None of the choices is correct.
Satellite communication is quite effective using either analog OR digital transmission.
Sound can't be used for satellite communication at all. (There's no medium to carry the sound to or from the satellite, and if there were, then the round-trip up and down through a geostationary satellite would take at least a minute at the sea-level speed of sound.)
Cellular devices can work but aren't required.
Answer:

Explanation:
As we know that the small particle is in equilibrium at an angle of 16 degree with the vertical
so here we can use force balance in vertical and horizontal direction


now from above equation we have

also by division of above two equations we have


now from above equation again




Answer:
So speed of electron will be 
Explanation:
We have given potential difference V = 9.9 KV
Charge on electron 
So energy of electron 
This energy of electron will be equal to kinetic energy of electron
So 


So speed of electron will be 
Answer:
15.38 m.
Explanation:
The kinetic energy of the block is equal to potential energy of spring at maximum compression
1/ 2 m V² = 1 /2 K X²
m is mass of block , V is its velocity , K is spring constant and X is maximum compression or its amplitude.
X = 
Putting the values
x = 
= 15.38 m.
Answer:
500x
Explanation:
A microscope had an eyepiece magnification of 10x
The objective lens magnification is 50x
Therefore the total magnification can be calculated as follows
= 10 × 50
= 500x
Hence the total Magnificattion is 500x