The time for the echo to return is directly proportional to the distance. vw = fλ. In a given medium under fixed conditions, vw is constant, so that there is a relationship between f and λ; the higher the frequency, the smaller the wavelength.
Answer:
AT
Explanation:
Dimensions of current = A
Dimensions of time = T
Current = Charge / time
Therefore Charge = Current × time
[Charge] = [Current] × [time]
= AT
Answer:
B. The same on the moon.
Explanation:
The density of an object is the ratio of the mass contained by the object to the volume occupied by that mass.

When the object is taken from the earth to anywhere in the universe, its mass remains constant. The dimensions of the object and hence its volume also remains constant anywhere in the universe.
Therefore, the density of the object will also remain the same as it depends upon the mass and the volume of the object.
So, the correct option is:
<u>B. The same on the moon.</u>
la separación mecánica de un sólido de grano grueso, insoluble, en un líquido; consiste en verter cuidadosamente el líquido, después de que se ha sedimentado el sólido. Por este proceso se separan dos líquidos miscibles, de diferente densidad, por ejemplola separación de un sólido disuelto en un líquido, por calentamiento, hasta que hierve y se transforma en vapor. Como no todas las sustancias se evaporan con la misma rapidez, el sólido disuelto se obtiene en forma pura, agua y aceite.