Answer:
(a)
(b)
Explanation:
Part (a)
The total length of copper cord L=86.3 m
The cross sectional area A=1.71×10⁻⁶m²
The resistivity of copper p=1.72×10⁻⁸Ω
Thus the resistance of extension cord is
Part (b)
The resistance of trimmer Rt=17.9 ohms
When voltage of 120V is applied then the current I is passing through series circuit is
Thus the voltage across the trimmer is:
The most reactive element of this list is Chlorine, the next most reactive is bromine, and the least reactive is iodine.
All of these three elements are group 7 elements in the periodic table. It is known that the reactivity of group 7 elements decreases down the group. The most reactive element in this group is Flourine with reactivity decreasing down the group.
The reason for this decrease in reactivity is that as you go down the group, the distance between the positive nucleus that attracts valence electrons increases, decreasing the electrostatic attraction between the nucleus and the outer electrons. The other reason is that the electrons in lower energy levels closer to the nucleus repel and shield the electrons in the outermost shell or energy level of the atom.
Chlorine>Bromine>Iodine.
The position of the first ball is
while the position of the second ball, thrown with initial velocity , is
The time it takes for the first ball to reach the halfway point satisfies
We want the second ball to reach the same height at the same time, so that
Explanation:
u=0, v=?, a=5m/s², t=8sec
So, by the formula,
v=u+at
v=0+5×8
v=40m/s.
hope this helps you .
You don't need to do any calculations, you are already given that n=1.5
n is index of refraction. it's 1.5