A hard rubber plastic comb is made out of rubber so it doesn't conduct electricity. This means that it is an insulator. Unlike a conductor (a metal comb), an insulator keeps the electrons at the place of where it was rubbed instead of equally distributing them around the surface of the comb.
In a metal comb, the charges within the comb move around while in the rubber comb they can't move around because in an insulator, it doesn't allow the movement of charges.
The potential energy as it reaches a height of 0.63 meters is mgh
Since total mechanical energy is conserved, Set that equal to the initial kinetic energy which is 0.5mv^2
2*9.8*0.63 = 0.5*2*v^2
12.348 = v^2
3.51 = v
That's it's initial speed.
Answer:
E = h f and since f = c / λ we have E = h c / λ
Thus λ = h c / E
Also, 1 ev = 1.6E-19 C
λ = 6.63E-34 * 3.0E8 / (1.6 * 1.6E-19)
λ = 6.63 * 3.0 / (1.6 * 1.6) * E-7
λ = 7.77E-7 = 777 nanometers
(B) is correct
Distance / speed. So, 63/35. Answes is 1.8
