Duas partículas iguais (Q1=Q2) eletricamente carregadas são colocadas no vácuo a uma distância de 30 cm. A força de interação entre essas cargas é:
Q1 = Q2 = 8x.10^-6C

a) de repulsão e igual a 6,4N
b) de repulsão e igual a 1,6N
c) de atração e igual a 6,4N
d) de atração e igual a 1,6N

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.

magnets not strong enough

explanation:

the ima (higher than 1m) will be greater than the ima with the height of 1m.