3. Ampere is the base unit for electric current.
The different types of microscopes are all necessary because not all experiments require the same level of magnification. For dissections low magnification is sufficient, so a dissecting microscope works very well, while for viewing single cells the 1000 fold magnification of a compound light microscope is more accurate.
The de Broglie hypothesis proposed that all particles have wave-like properties, with the wavelength being inversely proportional to the velocity of the particle.
Therefore as the velocity (speed in this question) increases, the wavelength *decreases*.
