The answer is B because if you use process of elimination, you find that A is invalid because Venus is the second planet. C is out because Mars is the 4th planet. D is out because we are nowhere near the Andromeda Galaxy. We are millions of light years away.
C. Thick wire and cold temperature.
Explanation:
The resistance of a wire is given by: R = (ρL)/A
where ρ is the resistivity of the material, L is the length of the wire, A is the cross-sectional area of the wire.
From the formula, we see that the thicker the wire, the larger A, therefore the smaller the resistivity. so, a thick wire will have lower resistivity.
Moreover, the resistance of a wire increases with the temperature. In fact, high temperatures mean more motion of the atoms/electrons inside the wire, so more resistance to the flow of current through it. Therefore, colder temperature means lower resistance.
So, the correct option is thick wire and cold temperature.
Answer:
Coefficient of friction.
Explanation:
The amount of friction divided by the weight of an object is equal to the coefficient of friction. It is a dimensional less number. It can be given by :
N is normal force.
= coefficient of friction
Answer:
The acceleration of the proton is 2.823 x 10¹⁷ m/s²
The acceleration of the electron is 5.175 x 10²⁰ m/s²
Explanation:
Given;
distance between the electron and proton, r = 7 x 10⁻¹⁰ m
mass of proton, 
= 1.67 x 10⁻²⁷ kg
mass of electron, 
= 9.11 x 10⁻³¹ kg
The attractive force between the two charges is given by Coulomb's law;
where;
k is Coulomb's constant = 9 x 10⁹ Nm²/c²
Acceleration of proton is given by;
F = ma
Acceleration of the electron is given by;
The acceleration due to gravity is g/4
The acceleration above the earth surface is given by the relation
g^'=gr^2/〖(h+r)〗^2
Since the satellite orbits the earth in a orbit of radius equal to earth radius, therefore
g^'=(gr^2)/〖(r+r)〗^2 =g/4
Thus the acceleration due to gravity on the satellite is g/4.
