3. the angular dispersion of a prism depends on
a. the index of refraction only b. the angle of
incidence as well as the index of refraction c. the
angle of incidence only d. the hi thickness of the
prism e, the prism angie.

The angular dispersion of a prism depends on the index of refraction only.

Explanation:

The angular dispersion of a prism mainly depends upon the refractive index of a material. And this refractive index is dependent on the wavelength of light. Each colour possesses its own characteristic and the wavelength is also different. There has been a relation between refractive index of a material and wavelength of light  higher the wavelength of the colour, greater would be the dispersion of light. As like when we passes light from a prism, according to this principle, the colours are dispersed.  

All the other options are incorrect as cannot decide angle of dispersion.

two charges are fixed in place on the x-axis as shown. the charge at x = 0 is negative and has magnitude q = 2 μcoulombs (1 μcoulomb = 10-6 coulombs). the charge at x = d, (d = +12 cm), is positive and has magnitude q = 4 μcoulombs. find a point x = xo along the x-axis at which the electric field is zero.